In vivo regulation of phenylalanine hydroxylation to tyrosine, studied using enrichment in apob-100
|
|
- Shona McKenzie
- 6 years ago
- Views:
Transcription
1 Am J Physiol Endocrinol Metab 294: E475 E479, First published November 27, 2007; doi: /ajpendo TRANSLATIONAL PHYSIOLOGY In vivo regulation of phenylalanine hydroxylation to tyrosine, studied using enrichment in apob-100 Mahroukh Rafii, 1 Jane M. McKenzie, 1 Susan A. Roberts, 1 George Steiner, 3 Ronald O. Ball, 2 and Paul B. Pencharz 1 1 Departments of Nutritional Sciences and Paediatrics, University of Toronto, The Research Institute, The Hospital for Sick Children, Toronto, Ontario; 2 Department of Agriculture, Food and Nutritional Sciences, University of Alberta, Edmonton; and 3 Department of Endocrinology, Toronto General Hospital, Toronto, Ontario, Canada Submitted 18 September 2007; accepted in final form 26 November 2007 Rafii M, McKenzie JM, Roberts SA, Steiner G, Ball RO, Pencharz PB. In vivo regulation of phenylalanine hydroxylation to tyrosine, studied using enrichment in apob-100. Am J Physiol Endocrinol Metab 294: E475 E479, First published November 27, 2007; doi: /ajpendo Phenylalanine hydroxylation is necessary for the conversion of phenylalanine to tyrosine and disposal of excess phenylalanine. Studies of in vivo regulation of phenylalanine hydroxylation suffer from the lack of a method to determine intrahepatocyte enrichment of phenylalanine and tyrosine. apob-100, a hepatic export protein, is synthesized from intrahepatocyte amino acids. We designed an in vivo multi-isotope study, [ 15 N]phenylalanine and [ 2 H 2 ]tyrosine to determine rates of phenylalanine hydroxylation from plasma enrichments in free amino acids and apob-100. For independent verification of apob-100 as a reflection of enrichment in the intrahepatocyte pool, [1-13 C]lysine was used as an indicator amino acid (IAA) to measure in vivo changes in protein synthesis in response to tyrosine supplementation. Adult men (n 6) were fed an amino acid-based diet with low phenylalanine (9 mg kg 1 day 1, 4.54 mol kg 1,h 1 ) and seven graded intakes of tyrosine from 2.5 (deficient) to 12.5 (excess) mg kg 1 day 1. Gas chromatography-quadrupole mass spectrometry did not detect any tracer in apob-100 tyrosine. A new and more sensitive method to measure label enrichment in proteins using isotope ratio mass spectrometry demonstrated that phenylalanine hydroxylation measured in apob-100 decreased linearly in response to increasing tyrosine intake and reached a break point at 6.8 mg kg 1 day 1. IAA oxidation decreased with increased tyrosine intake and reached a break point at 6.0 mg kg 1 day 1. We conclude: apob-100 is an accurate and useful measure of changes in phenylalanine hydroxylation; the synthesis of tyrosine via phenylalanine hydroxylation is regulated to meet the needs for protein synthesis; and that plasma phenylalanine does not reflect changes in protein synthesis. apolipoprotein B-100 THE HYDROXYLATION OF PHENYLALANINE to tyrosine is considered to be the most important determinant of phenylalanine homeostasis because it is the rate-limiting step in the oxidation of phenylalanine to CO 2 and water (23). Phenylalanine hydroxylase has been shown to occur in both the liver and kidney, and in humans the liver enzyme is predominant, with an average activity level four to five times that in the kidney in vitro (1). Address for reprint requests and other correspondence: P. B. Pencharz, Division of Gastroentrology and Nutrition, The Hospital for Sick Children, 555 University Ave., Toronto, ON, Canada M5G 1X8 ( There are contradictory reports in vivo in humans. Moller et al. (18), using measurement of phenylalanine uptake and tyrosine release across the kidney and splanchnic bed, concluded that the kidney is an important site for phenylalanine-to-tyrosine production. Conversely, Jones et al. (12), using [ 14 C]phenylalanine, observed a mild impairment in the hydroxylation of phenylalanine that did not produce marked changes in plasma or urinary metabolites of phenylalanine in uremic adults. Clarke and Bier (5) developed an in vivo model to estimate the rate of phenylalanine hydroxylation in fasted humans by use of stable isotope tracers. This model used the ratio of the plasma enrichment of tyrosine to phenylalanine, representing the product and precursor pools of hydroxylation, respectively, and tyrosine flux to calculate the rate of phenylalanine hydroxylation (5). Although originally developed for use in the fasted state, the Clarke and Bier model, and its modified version (19), were subsequently applied to studies in the fed state in parenterally fed neonates using intravenously administered isotope infusions (2, 4, 7, 15, 26, 28). The results of these studies indicated that parenterally fed neonates have the ability to hydroxylate phenylalanine. However, a follow-up appraisal by our group (10), using data from a study of parenterally fed neonatal piglets, questioned the quantitative validity of this measure of phenylalanine hydroxylation under certain circumstances. The results indicated that, at low tyrosine and high phenylalanine intakes, the estimation of rate of hydroxylation exceeded the intake of phenylalanine, indicating net tissue protein breakdown. However, those piglets were shown to be actively growing and depositing body protein. It was therefore concluded that, by use of this model at intakes of tyrosine below the mean requirement as estimated by House et al. (9), and at high intakes of phenylalanine, measurements of phenylalanine hydroxylation were overestimated. Subsequent examination of results from previous studies of phenylalanine metabolism in TPN-fed neonates (2, 15, 26) also indicates that rates of hydroxylation appeared to be overestimated. Similarly, we showed in adult humans that rates of phenylalanine hydroxylation are overestimated (27) at low tyrosine intakes. Indeed, it was not until the tyrosine intake reached 10.5 mg kg 1 day 1 (y x, R ) that the rate of hydroxylation fell below the phenylalanine The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact /08 $8.00 Copyright 2008 the American Physiological Society E475
2 E476 intake of 4.54 mol kg 1 h 1 (9.1 mg kg 1 day 1 ) (see Fig. 4). Therefore, we believe that all the previous in vivo estimates of phenylalanine hydroxylation may be erroneous. A potential source of error in the calculation of phenylalanine hydroxylation with the current model involves the site of sampling of amino acid enrichments. The issue of what is the most appropriate free amino acid pool to sample in isotope studies of amino acid metabolism has been well recognized (3, 11, 21). Most studies of amino acid metabolism in humans have traditionally been conducted using plasma amino acid enrichments, since it was suggested to be the best representation of whole body amino acid kinetics (30), and also due to lack of a suitable marker of intracellular enrichment. The notable exception is the use of the enrichment of ketoisocaproate (KIC) as a reflection of intracellular leucine enrichment (17). apob-100 has been shown to represent the amino acid enrichments of the hepatic intracellular pool (21): the site of phenylalanine hydroxylation. Because very-low-density lipoprotein (VLDL) particles are rapidly processed to higherdensity particles, the apob-100 contained within the VLDL fraction has a very high rate of turnover. It is sufficiently rapid that, during the course of a tracer amino acid infusion of less than 12 h, the apob-100 enrichment reaches isotopic equilibrium (21). By definition, once this status has been achieved the isotopic enrichment of the tracer amino acid in the VLDL apob-100 is a direct measurement of the enrichment of the intracellular hepatic pool from which it was derived. In the present study, the main objective was to compare estimates of phenylalanine hydroxylation across a range of tyrosine intakes, determined using plasma and apob-100 phenylalanine and tyrosine enrichments, with a measurement of in vivo change in protein synthesis. At fixed and deficient intakes of dietary phenylalanine, the rate of hydroxylation was measured at seven graded levels of tyrosine intake using the enrichment in either plasma and apob-100 amino acids following oral dosing of L-[ 15 N]phenylalanine and L-[3,3-2 H 2 ]tyrosine. Rates of whole body protein synthesis were made with L-[ 13 C]lysine using indicator amino acid oxidation (20). MATERIALS AND METHODS Subjects. Six healthy adult male volunteers participated in the study on an outpatient basis in the Clinical Investigation Unit at the Hospital for Sick Children (HSC), Toronto, Canada. Subject characteristics are detailed in Table 1. Each subject received all diet treatments. More details on the subjects and their diet and energy intakes can be found in our previous, corollary papers (22, 27). Tracer protocol and experimental design. Subjects were randomly allocated to receive each of the seven different dietary intakes of 3.0, Table 1. Subject characteristics Subject Age, yr Height, m Weight, kg Energy Intake, MJ/day* Mean SD *Calculated from the 1985 FAO/WHO/UN predictive equations, multiplied by an activity factor of 1.7 (8). 4.5, 6.0, 7.5, 9.0, 10.5, and 12.0 mg kg 1 day 1. Each study consisted of 2 days on a controlled protein intake of 1 g kg 1 day 1 followed by a single study day for the measurement of phenylalanine hydroxylation. On the study day, phenylalanine hydroxylation was measured using L-[ 15 N]phenylalanine and L-[3,3-2 H 2]tyrosine at a protein intake of 1 g kg 1 day 1. Indicator amino acid oxidation (IIAAO) measurements were made simultaneously using L-[1-13 C]lysine. All isotopes were given orally at hourly intervals so as to simulate a constant infusion for a total of 5 h. The study periods were separated by at least 1 wk, and all studies were carried out within 3 mo (22, 27). Sample collection and analysis. Detailed steps for plasma and breath collections and analyses are outlined in our previous papers (22, 27). Arterialized venous blood samples (15 ml) were also collected into tubes containing 1.5 ml of 15% Na 4EDTA-H 2O for the analysis of amino acid enrichments from apob-100. Arterialized venous blood was obtained in a similar method to that mentioned earlier. Plasma was separated for the analysis of amino acid enrichments in apob-100 by ultracentrifugation (Optima LE-80K Ultracentrifuge; Beckman Coulter, Fullerton, CA) at 4 C at 39,000 rpm for 16 h. The top VLDL fraction was aspirated into a separate tube and delipidated. The apolipoproteins B-48 and B-100 from the VLDL fraction were then separated by the SDS-PAGE technique (13). The bands were read against an apob-100 standard curve obtained from human LDL (1.035 d g/ml). Freeze-dried (Labconco Freeze Dry System; Labconco, Kansas City, MO) gel sections of apob-100 were then hydrolyzed in 300 l of 6.0 N HCl plus 0.5% phenol at 110 C in vacuum reaction vessels placed in a heated work station (Eldex Hydrolysis and Derivatization Station; Elex Laboratories, Napa, CA) for 24 h. The hydrolyzed samples were cooled to room temperature and frozen at 20 C for 20 min. This was followed by centrifugation at 3,000 rpm for 10 min. The separated supernatant fractions were dried under Speed Vac (Labconco Freeze Dry System). The dried samples were reconstituted in 50 l of 0.1% formic acid (FA). Phenylalanine and tyrosine fractions were separated from each sample by a fraction collector (Fraction Collector Frac-100; Pharmacia, Uppsala, Sweden) attached to an HPLC (Dionex, Sunnyvale, CA). The amino acids were separated by a Dionex Acclaim 120 A PA (Polar Advantage), C 16, mm, 5- m column. An isocratic gradient at 0.75 ml/min of 0.1% FA at an oven temperature of 37 C was used. The phenylalanine and tyrosine fractions were freeze-dried overnight for enrichment analysis by continuous-flow isotope ratio mass spectrometer (CFIRMS; 20/20, ANCA GSL; Europa Scientific, Crewe, UK). The freeze-dried samples were reconstituted in 50 l of deionized water and transferred to 6 4-mm tin capsules. The samples were evaporated to dryness on a heating block at 70 C. The dried samples in the tin capsules were squelched and combusted in the elemental analyzer (ANCA) unit attached to the CFIRMS. The samples were run against urea working standards that were calibrated against international standards [Urea Standard Reference Material 2141 Batch no ; National Institute of Standards and Technology (NIST), Maryland] to calculate the APE of [ 15 N]phenylalanine and [ 15 N]tyrosine. Since the amount of phenylalanine and tyrosine extracted from the hydrolysates ranged from 2 and 1 g, we determined enrichment at both 1 and 2 g of nitrogen. Both showed very similar results, and the 15 N enrichment curves for 1 g of nitrogen is shown (Fig. 1). Estimation of isotope kinetics. Phenylalanine kinetics were calculated according to the stochastic model of Matthews et al. (16), as we have previously employed (31). Briefly, stable isotope-labeled amino acid is given as a continuous infusion, and the enrichment of the pool increases until a plateau is reached. The initial increase in the enrichment of the pool is relative to the pool size and turnover rate. The enrichment of the plateau represents the rate of turnover of the pool, and this relationship is used to calculate the flux of the free amino acid pool: Q i(e i/e), where, i rate of infusion of the
3 E477 Fig. 1. One-microgram 15 N enrichment curve derived by combustion isotope ratio mass spectrometry measurements of of a [ 15 N]glycine enriched standard. Values of enrichment are expressed in atoms percent excess (APE). isotope, E i enrichment of the labeled amino acid, and E enrichment of the pool at plateau. This equation can be modified to account for the difference of the isotope infusion on the flux rate (17): Q i[(e i/e) 1].Isotopic steady state in the metabolic pool was represented by plateaus in free [ 15 N]phenylalanine, [ 15 N]tyrosine, and [3,3-2 H 2]tyrosine in plasma. The occurance of a plateau was defined by visual inspection, the absence of a significant slope, assessed by linear regression analysis, and by the coefficient of variation of the points making up the plateau (n 4) being less than 5%. The mean ratios of the enriched peaks (m 1 and m 2) to the unenriched (m) for each amino acid at both the baseline and plateau samples were used to calculate molecules percent excess (MPE). Phenylalanine flux ( mol kg 1 h 1 ) was measured during isotopic steady state from the dilution of the L-[1-15 N]phenylalanine infused into the plasma metabolic pool. Tyrosine flux was estimated from the dilution of the [3,3-2 H 2]tyrosine infused. Phenylalanine hydroxylation in both plasma and the apob-100 samples were calculated from the conversion of the [ 15 N]phenylalanine to [ 15 N]tyrosine and from the independent measurement of tyrosine flux according to the model of Clarke and Bier (5): Q pt Q t [E t/e p], where Q pt is the rate of phenylalanine hydroxylation ( mol kg 1 h 1 ), Q t is the tyrosine flux ( mol kg 1 h 1 ) estimated from [3,3-2 H 2]tyrosine, and E t/e p is the ratio of the enrichments of [ 15 N]tyrosine to [ 15 N]phenylalanine in either plasma or in apob-100. Oxidation of 13 C lysine was calculated from the appearance of 13 CO 2 in breath (22). Data analysis. Repeated-measures analysis of variance was performed to assess the effect of tyrosine intake on phenylalanine hydroxylation, phenylalanine flux, tyrosine flux and lysine oxidation. Where an effect was identified, the data were analyzed using a two-phase linear crossover model (29) (Proc Mixed, SAS 8.21 for Windows; SAS Institute Cary, NC) to assign a break point to the response. The variance around the break point (95% confidence interval) was determined using Feiller s theorem (24). Results were considered to be statistically significant at P Fig. 2. Phenylalanine hydroxylation to tyrosine measured by apob-100. Mean ( SE) phenylalanine hydroxylation at graded tyrosine intakes. Dotted vertical lines represent 95% confidence limits of break point (6.8 mg kg 1 day 1 ) estimate. using IAAO (22). The break point estimate using IAAO methodology was found to be 6.0 mg tyrosine kg 1 day 1. Phenylalanine hydroxylation to tyrosine measured by plasma enrichments is shown in Fig. 4 (mean SE, modified from Ref. 27). In the plasma, no identifiable break point was seen in phenylalanine hydroxylation in response to tyrosine intake levels, using a two-phase linear regression crossover model. Conversely, linear regression analysis showed a significant effect of tyrosine intake on phenylalanine hydroxylation (P 0.002), such that the rate of hydroxylation was higher following a lower intake of tyrosine. The relationship is defined by the equation, y x (R , SE 2.02). Dietary phenylalanine intake was 4.54 mol kg 1 h 1. It was not until a tyrosine intake of 10.5 mg kg 1 day 1 that estimated phenylalanine hydroxylation equaled phenylalanine intake. This contrasts with the phenylalanine hydroxylation estimates that were derived from apob-100 enrichment where even at the lowest tyrosine intake phenylalanine hydroxylation was less than phenylalanine intake. RESULTS The mean ( SE) response of phenylalanine hydroxylation in the apob-100 protein to variations in tyrosine intake is shown in Fig. 2. In general, phenylalanine hydroxylation decreased from tyrosine intakes of 3.0 to 6.8 mg kg 1 day 1, after which point there was no change in slope with further increase in tyrosine intake levels. Two-phase linear regression crossover model was the best-fit model for our data, and the break point estimate was found to be 6.8 mg kg 1 day 1. Figure 3 shows the production of 13 CO2 (V 13 CO 2 ; mean SE) from the oxidation of L-[1-13 C]lysine at graded tyrosine intakes Fig CO 2 production (V 13 CO 2) from the oxidation of L-[1-13 C]lysine at graded tyrosine intakes (23), reproduced with permission from The American Journal of Clinical Nutrition. Mean SE V 13 CO 2 from the oxidation of L-[1-13 C]lysine at graded tyrosine intakes. Dotted vertical lines represent 95% confidence limits of break point (6.0 mg kg 1 day 1 ) estimate.
4 E478 Fig. 4. Phenylalanine hydroxylation to tyrosine measured by plasma enrichments modified from Ref. 26, reprinted with permission from Elsevier. Mean ( SE) phenylalanine hydroxylation at graded tyrosine intakes. Linear regression analysis showed a significant effect of tyrosine intake on phenylalanine hydroxylation (P 0.002), such that the rate of hydroxylation was higher following a lower intake of tyrosine. The relationship is defined by the equation: y x (R , SE 2.02). Subject 2 data for a tyrosine intake of 3 mg kg 1 day 1 were technically unsatisfactory and were thus omitted; therefore, at this level of tyrosine intake, there are only 5 data points. For all other levels, there are 6 data points, for a total of 41 data points. Dietary phenylalanine intake was 4.54 mol kg 1 h 1. DISCUSSION There are limited data in the literature on the effects of tyrosine on phenylalanine hydroxylation, all of which are in in vitro rat liver (6) or hepatocytes (25); there are none in human tissue. Shiman and Gray (25) found in primary rat hepatocyte cultures that tyrosine had little effect on phenylalanine hydroxylation. Conversely, Davis and Kaufman (6) showed in rat liver that tyrosine can uncouple tetrahydrohydrobiopterin (BH-4) from a tight complex with phenylalanine hydroxylase, which then results in the oxidation of BH-4 without any hydroxylation of phenylalanine to tyrosine. Phenylalanine hydroxylase is strongly influenced by substrate levels, a biologically important mechanism that protects against the toxic accumulation of phenylalanine (14). The fate of the product of phenylalanine hydroxylation, tyrosine, has been shown to be dependent on tyrosine levels in the media of cultured rat hepatocytes (25). In the presence of excess tyrosine, the synthesized tyrosine is channeled within the hepatocyte to degradation (24). Using this data, Shiman and Gray developed a quantitative model of tyrosine and phenylalanine flux through hepatocytes, including consideration of tyrosine synthesis, degradation, plasma membrane transport, and tyrosine and phenylalanine use and release during protein turnover. As mentioned in the introductory section, in vitro studies of hepatic and renal phenylalanine hydroxylase activity suggest that the liver predominates. However, in vivo studies have suggested that the kidney may be an important site of phenylalanine conversion to tyrosine (18). Conversely, other in vivo studies in humans have suggested that the phenylalanine catabolism in uremia is only mildly impaired (12). The present studies focus on the validity and utility of a marker of intrahepatocyte (apob-100) amino acid enrichments as a more direct in vivo measurement of phenylalanine hydroxylation. We chose to do so using graded intakes of the product, tyrosine, since earlier work had suggested that tyrosine might inhibit phenylalanine hydroxylation to tyrosine (6, 25). In addition, in light of the uncertainty regarding the importance (predominance) of hepatic phenylalanine metabolism, we chose to use an independent marker of whole body protein metabolism, IAAO. The basis of the technique is that the indicator (in this case lysine) is partitioned either to incorporation into protein (protein synthesis) or to oxidation (20). Hence, in Fig. 3, as tyrosine intake increases from lower intakes and the rate of lysine oxidation decreases, so protein synthesis also increases until the break point at a tyrosine intake of 6.0 mg kg 1 day 1. After the break point, increases in tyrosine intake have no effect on lysine oxidation and, hence, on whole body protein synthesis. The most likely source of error in the present methods for determination of phenylalanine hydroxylation involves the site of sampling of amino acid enrichments. Hepatic export proteins such as apob-100 (21) may provide more accurate estimates of liver intracellular amino acid enrichment, because the hydroxylation of phenylalanine occurs primarily in the cytosol of the hepatocytes. Analysis for apob-100 in the present experiment showed that with increasing tyrosine intake the rate of phenylalanine hydroxylation decreased linearly from 3.0 to 6.8 mg kg 1 day 1, after which point there was no further decrease (slope not significantly different from zero) with further increases in tyrosine intake (Fig. 2). At low tyrosine intake, phenylalanine was hydroxylated to provide tyrosine to support protein synthesis. Once sufficient dietary tyrosine was provided to optimize protein synthesis, there was a constant rate of phenylalanine hydroxylation. The plateau level of phenylalanine hydroxylation, after the break point shown in Fig. 2, represents the first direct in vivo estimate of the minimal obligatory rate of phenylalanine hydroxylation in human adults during feeding. The hydroxylation estimates obtained from apob-100 are more rational than previous estimates based on plasma enrichment (Fig. 4), since they do not exceed dietary phenylalanine intake levels. There was very close correspondence between the pattern of the apob-100-derived estimates of phenylalanine hydroxylation and the pattern of (indicator) lysine oxidation. The very similar break points in hydroxylation (6.8 mg kg 1 day 1 ) and indicator oxidation 6.0 mg kg 1 day 1 (protein synthesis) clearly demonstrate for the first time in vivo that dietary tyrosine regulates phenylalanine hydroxylation to optimize whole body protein synthesis. This is also the first clear demonstration that enrichment in apob-100 gives results that agree with in vivo changes in protein synthesis. The present data also support the concept that, in vivo in the fed state, the liver plays a major role in the hydroxylation of phenylalanine to tyrosine. The observations of Moller et al. (18) are in the fasted state. It is currently unclear whether the feeding state is a key determinant. However, the studies of Jones et al. (12) were extended to measure cumulative oxidation of phenylalanine over 24 h, hence covering fed and fasted states and also showed a minor role for the kidney. In conclusion, analysis of the enrichment in apob-100 protein is a new and highly improved in vivo isotope model of hepatic intracellular enrichment of amino acids. This model can be used in the study of in vivo metabolism of most amino acids via protein synthesis. Using this new apob-100 model,
5 we have shown that dietary tyrosine regulates hepatic phenylalanine hydroxylation to provide tyrosine for whole body protein synthesis. ACKNOWLEDGMENTS We thank Mead Johnson, Canada, for supplying the protein-free powder. J. M. McKenzie s current address: Queen Margaret University, Edinburgh, EH12 8TS, Scotland, UK. S. A. Roberts current address: The Beverage Institute for Health and Wellness, The Coca-Cola Company, 2000 St. James Pl., Houston, TX Jane M. McKenzie has changed her name from Jane M. Thorpe. GRANTS This study was supported by CHIR Grant no. FRN REFERENCES 1. Ayling JE, Helfand GD, Pirson WD. Phenylalanine hydroxylase from human kidney. Enzyme 20: 6 19, Castillo L, Yu YM, Marchini JS, Chapman TE, Sanchez M, Young VR, Burke JF. Phenylalanine and tyrosine kinetics in critically ill children with sepsis. Pediatr Res 35: , Cayol M, Boirie Y, Prugnaud J, Gachon P, Beaufrere B, Obled C. Precursor pool for hepatic protein synthesis in humans: effects of tracer route infusion and dietary proteins. Am J Physiol Endocrinol Metab 270: E980 E987, Clark SE, Karn CA, Ahlrichs JA, Wang J, Leitch CA, Denne SC. Acute changes in leucine and phenylalanine kinetics produced by parenteral nutrition in premature infants. Pediatr Res 41: , Clarke JT, Bier DM. The conversion of phenylalanine to tyrosine in man. Direct measurement by continuous intravenous tracer infusions of L-[ring- 2H5]phenylalanine and L-[1-13C] tyrosine in the postabsorptive state. Metabolism 31: , Davis MD, Kaufman S. Products of the tyrosine-dependent oxidation of tetrahydrobiopterin by rat liver phenylalanine hydroxylase. Arch Biochem Biophys 304: 9 16, Denne SC, Karn CA, Ahlrichs JA, Dorotheo AR, Wang J, Liechty EA. Proteolysis and phenylalanine hydroxylation in response to parenteral nutrition in extremely premature and normal newborns. J Clin Invest 97: , Food and Agriculture Organization/World Health Organization/ United Nations. Energy and protein requirements. World Health Organization 724: , House JD, Pencharz PB, Ball RO. Phenylalanine requirements determined by using L-[1 14C]phenylalanine in neonatal piglets receiving total parenteral nutrition with a high phenylalanine content. Am J Clin Nutr 65: , House JD, Thorpe JM, Wykes LJ, Pencharz PB, Ball RO. Evidence that phenylalanine hydroxylation rates are overestimated in neonatal subjects receiving total parenteral nutrition with a high phenylalanine content. Pediatr Res 43: , Jahoor F, Burrin DG, Reeds PJ, Frazer M. Measurement of plasma protein synthesis rate in infant pig: and investigation of alternative tracer approaches. Am J Physiol Regul Integr Comp Physiol 267: R221 R227, Jones MR, Kopple JD, Swendseid ME. Phenylalanine metabolism in uremic and normal man. Kidney Int 14: , E Karpe F, Hamsten A, Uffelman K, Steiner G. Apolipoprotein B-48. Methods Enzymol 263: , Kaufman S. Regulation of the activity of hepatic phenylalanine hydroxylase. Adv Enzyme Regul 25: 37 64, Kilani RA, Cole FS, Bier DM. Phenylalanine hydroxylase activity in preterm infants: is tyrosine a conditionally essential amino acid? Am J Clin Nutr 61: , Matthews DE, Motil KJ, Rohrbaugh DK, Burke JF, Young VR, Bier DM. Measurement of leucine metabolism in man from a primed, continuous infusion of L-[1-13 C]leucine. Am J Physiol Endocrinol Metab 238: E473 E479, Matthews DE, Schwarz HP, Yang RD, Motil KJ, Young VR, Bier DM. Relationship of plasma leucine and alpha-ketoisocaproate during a L-[1 13C]leucine infusion in man: a method for measuring human intracellular leucine tracer enrichment. Metabolism 31: , Moller N, Meek S, Bigelow M, Andrews J, Nair KS. The kidney is an important site for in vivo phenylalanine-to-tyrosine conversion in adult humans: A metabolic role of the kidney. Proc Nat Acad Sci USA 97: , Peeler TC, Stephenson MB, Einspahr KJ, Thompson GA. Lipid characterization of an enriched plasma membrane fraction of dunaliella salina grown in media of varying salinity. Plant Physiol 89: , Pencharz PB, Ball RO. Different approaches to define individual amino acid requirements. Annu Rev Nutr 23: , Reeds PJ, Hachey DL, Patterson BW, Motil KJ, Klein PD. VLDL apolipoprotein B-100, a potential indicator of the isotopic labelling of the hepatic protein synthetic precursor pool in humans: studies with multiple stable isotopically labelled amino acids. J Nutr 122: , Roberts SA, Thorpe JM, Ball RO, Pencharz PB. Tyrosine requirement of healthy men receiving a fixed phenylalanine intake determined by using indicator amino acid oxidation. Am J Clin Nutr 73: , Scriver CRKS, Eisensmith RC, Woo SLC. The hyperphenylalaninaemias. In: The Metabolic and Molecular Basis of Inherited Diseases (7th ed.), edited by Scriver CR, Beaudet AL, Sly WS, Valle D. New York: McGraw-Hill, 1995, p Seber GAF. Linear regression analysis. New York: John Wiley, Shiman R, Gray DW. Formation and fate of tyrosine. Intracellular partitioning of newly synthesized tyrosine in mammalian liver. J Biol Chem 273: , Shortland GJ, Walter JH, Fleming PJ, Halliday D. Phenylalanine kinetics in sick preterm neonates with respiratory distress syndrome. Pediatr Res 36: , Thorpe JM, Roberts SA, Ball RO, Pencharz PB. Effect of tyrosine intake on the rate of phenylalanine hydroxylation in adult males. Metabolism 49: , Van Toledo-Eppinga L, Kalhan SC, Kulik W, Jakobs C, Lafeber HN. Relative kinetics of phenylalanine and leucine in low birth weight infants during nutrient administration. Pediatr Res 40: 41 46, Wang Z, Goonewardene LA. The use of MIXED models in the analysis of animal experiments with repeated measures data. Can J Anim Sci 84: 1 11, Waterlow JC, Garlick PJ, Millward DJ. General principles of the measurement of whole-body protein turnover. In: Protein Turnover in Mammalian Tissues and in Whole Body, edited by Waterlow JC, Garlick PJ, Millward DJ. Amsterdam: Elsevier/North-Holland, 1978, p Zello GA, Pencharz PB, Ball RO. Phenylalanine flux, oxidation, and conversion to tyrosine in humans studied with L-[1-13 C]phenylalanine. Am J Physiol Endocrinol Metab 259: E835 E843, 1990.
Dietary protein intake affects albumin fractional synthesis rate in younger and older adults equally
Emerging Science Dietary protein intake affects albumin fractional synthesis rate in younger and older adults equally Anna E Thalacker-Mercer and Wayne W Campbell Inclusion of dietary protein in meals
More informationTyrosine requirement of healthy men receiving a fixed phenylalanine intake determined by using indicator amino acid oxidation 1 4
Tyrosine requirement of healthy men receiving a fixed phenylalanine intake determined by using indicator amino acid oxidation 1 4 Susan A Roberts, Jane M Thorpe, Ronald O Ball, and Paul B Pencharz ABSTRACT
More informationEvaluation of Stable Isotope Labeling Technique in Measuring the Tissues Protein Fractional Synthesis Rates in Rats
Available online at www.annclinlabsci.org Annals of Clinical & Laboratory Science, vol. 45, no. 2, 2015 187 Evaluation of Stable Isotope Labeling Technique in Measuring the Tissues Protein Fractional Synthesis
More informationProtein Recommendations: Time for an Update?
Protein Recommendations: Time for an Update? Rajavel Elango Ph.D. Assistant Professor Department of Pediatrics, School of Population and Public Health University of British Columbia Scientist Level 1 Nutrition
More informationDetermination of kinetic parameters of apolipoprotein B metabolism using amino acids labeled with stable isotopes
Determination of kinetic parameters of apolipoprotein B metabolism using amino acids labeled with stable isotopes Klaus G. Parhofer, P. Hugh R. Barrett,t Dennis M. Bier,* and Gustav Schonfeld Division
More informationSkeletal muscle metabolism was studied by measuring arterio-venous concentration differences
Supplemental Data Dual stable-isotope experiment Skeletal muscle metabolism was studied by measuring arterio-venous concentration differences across the forearm, adjusted for forearm blood flow (FBF) (1).
More informationBranched-Chain Amino Acids: Metabolism, Physiological Function, and Application
Branched-Chain Amino Acids: Metabolism, Physiological Function, and Application Transamination of Leucine and Nitrogen Accretion in Human Pregnancy and the Newborn Infant 1 3 Satish C. Kalhan 4 and Prabhu
More informationLeucine requirement and splanchnic uptake of leucine in chronically undernourished adult Indian subjects 1 3
Leucine requirement and splanchnic uptake of leucine in chronically undernourished adult Indian subjects 1 3 Anura V Kurpad, Meredith M Regan, Tony Raj, Sureka Varalakshmi, Justin Gnanou, Prashanth Thankachan,
More informationEffects of Dietary Vitamin E Level and Source on Sow, Milk, and Piglet Concentrations of α-tocopherol 1
Effects of Dietary Vitamin E Level and Source on Sow, Milk, and Piglet Concentrations of α-tocopherol N. W. Shelton, J. L. Nelssen, M. D. Tokach, S. S. Dritz 2, R. D. Goodband, J. M. DeRouchey, H. Yang
More informationASSUMPTIONS AND DETAILS OF CALCULATIONS FOR FATTY ACID KINETICS
1 1 1 1 1 1 0 1 ASSUMPTIONS AND DETAILS OF CALCULATIONS FOR FATTY ACID KINETICS Our hypothesis was that many sources of palmitate (NEFA, lipogenesis, diet) could contribute to newly-synthesized VLDL-TG
More informationEffects of meal consumption on whole body leucine and alanine kinetics in young adult men
British Journal of Nutrition (1985), 53, 31-38 31 Effects of meal consumption on whole body leucine and alanine kinetics in young adult men BY LEONARD J. HOFFER1*, RUSSELL D. YANGl, DWIGHT E. MATTHEWS2,
More informationArginine Is Synthesized From Proline, Not Glutamate, in Enterally Fed Human Preterm Neonates
0031-3998/11/6901-0046 PEDIATRIC RESEARCH Copyright 2010 International Pediatric Research Foundation, Inc. Vol. 69, No. 1, 2011 Printed in U.S.A. Arginine Is Synthesized From Proline, Not Glutamate, in
More informationThe Pattern of Intestinal Substrate Oxidation Is Altered by Protein Restriction in Pigs
GASTROENTEROLOGY 2001;121:1167 1175 The Pattern of Intestinal Substrate Oxidation Is Altered by Protein Restriction in Pigs SOPHIE R. D. VAN DER SCHOOR,*, JOHANNES B. VAN GOUDOEVER,*, BARBARA STOLL,* JOE
More informationKidney, Splanchnic, and Leg Protein Turnover in Humans
Kidney, Splanchnic, and Leg Protein Turnover in Humans Insight from Leucine and Phenylalanine Kinetics Paolo Tessari, Giacomo Garibotto,* Sandro Inchiostro, Cristina Robaudo,* Stefano Saffioti,* Monica
More informationProtein requirement of healthy school-age children determined by the indicator amino acid oxidation method 1 4
Protein requirement of healthy school-age children determined by the indicator amino acid oxidation method 1 4 Rajavel Elango, Mohammad A Humayun, Ronald O Ball, and Paul B Pencharz ABSTRACT Background:
More informationLysine requirements of healthy adult Indian subjects, measured by an indicator amino acid balance technique 1 3
Lysine requirements of healthy adult Indian subjects, measured by an indicator amino acid balance technique 1 3 Anura V Kurpad, Tony Raj, Antoine El-Khoury, Louis Beaumier, Rebecca Kuriyan, Abhinash Srivatsa,
More informationCysteine Supplementation in Parenteral-fed Critically ill Neonates:
Cysteine Supplementation in Parenteral-fed Critically ill Neonates: A Randomized Trial Investigating Glutathione Synthesis Stephen B. Shew, M.D. UCLA Division of Pediatric Surgery Nov 29, 2006 Background
More informationDynamics of Human Whole Body Amino Acid Metabolism: Use of Stable Isotope Probes and Relevance to Nutritional Requirements1
J. Nutr. Sci. VitaminoL, 27, 395-413, 1981 Review Dynamics of Human Whole Body Amino Acid Metabolism: Use of Stable Isotope Probes and Relevance to Nutritional Requirements1 Vernon R. YOUNG Laboratory
More informationFormation and Fate of Tyrosine
THE JOURNAL OF BIOLOGICAL CHEMISTRY Vol. 273, No. 52, Issue of December 25, pp. 34760 34769, 1998 1998 by The American Society for Biochemistry and Molecular Biology, Inc. Printed in U.S.A. Formation and
More informationWhole body and skeletal muscle glutamine metabolism in healthy subjects
Am J Physiol Endocrinol Metab 280: E323 E333, 2001. Whole body and skeletal muscle glutamine metabolism in healthy subjects B. MITTENDORFER, 1 E. VOLPI, 2,4 AND R. R. WOLFE 1,3,4 Departments of 1 Surgery,
More informationOptimizing Nutritional Strategies to Promote Growth in Newborns
Optimizing Nutritional Strategies to Promote Growth in Newborns Teresa A. Davis, Ph.D. Professor of Pediatrics USDA/ARS Children s Nutrition Research Center, Baylor College of Medicine, Houston, TX Disclosure
More informationThe Effect of Casein Ingestion within a Milk Matrix on Muscle Protein Synthesis
The Effect of Casein Ingestion within a Milk Matrix on Muscle Protein Synthesis Department of Human Movement Science s.reiners@student.maastrichtuniversity.nl Abstract Isolated micellar casein has been
More information/07/ PEDIATRIC RESEARCH Vol. 61, No. 3, 2007 Copyright 2007 International Pediatric Research Foundation, Inc.
0031-3998/07/6103-0356 PEDIATRIC RESEARCH Vol. 61, No. 3, 2007 Copyright 2007 International Pediatric Research Foundation, Inc. Printed in U.S.A. Acute Effects of Enteral Nutrition on Protein Turnover
More information5th Amino Acid Assessment Workshop
5th Amino Acid Assessment Workshop The In Vivo Sparing of Methionine by Cysteine in Sulfur Amino Acid Requirements in Animal Models and Adult Humans 1,2 Ronald O. Ball,* y3 Glenda Courtney-Martin, y and
More informationAmino acids. Ing. Petrová Jaroslava. Workshop on Official Controls of Feed AGR 46230, , Ankara. Turkey ÚKZÚZ - NRL RO Praha 1
Amino acids Ing. Petrová Jaroslava Workshop on Official Controls of Feed AGR 46230, 6. 7. 12. 2011, Ankara. Turkey 6.12.2011 ÚKZÚZ - NRL RO Praha 1 Content of this presentation 1. Function of amino acids
More informationEvaluation of the Protein Requirement in Chinese Young Adults Using the Indicator Amino Acid Oxidation Technique *
Biomed Environ Sci, 2013; 26(8): 655-662 655 Original Article Evaluation of the Requirement in Chinese Young Adults Using the Indicator Amino Acid Oxidation Technique * LI Min 1, WANG Zhi Ling 2, GOU Ling
More informationUCLA Nutrition Bytes. Title. Permalink. Journal ISSN. Author. Publication Date
UCLA Nutrition Bytes Title Whey Protein- The Role of Protein Supplementation in Resistance Training Permalink https://escholarship.org/uc/item/07p2v5wd Journal Nutrition Bytes, 10(2) ISSN 1548-601X Author
More informationKansas Agricultural Experiment Station Research Reports
Kansas Agricultural Experiment Station Research Reports Volume 0 Issue 10 Swine Day (1968-2014) Article 1092 2004 Determination of the apparent and true ileal amino acid digestibility and digestible and
More informationEffects of flooding amino acids on incorporation of labeled amino acids into human muscle protein
Effects of flooding amino acids on incorporation of labeled amino acids into human muscle protein KENNETH SMITH, NIGEL REYNOLDS, SHAUN DOWNIE, AYYUB PATEL, AND MICHAEL J. RENNIE Department of Anatomy and
More informationProtein Metabolism and Endurance Exercise
DADCD Sports p Med 2007.-37 W-6): 337-340 0112-1642/07/0004-0337/544.95/0 rarck 2007 Adls Data Intormotlon BV. All rights reserved. Protein Metabolism and Endurance Exercise Martin J. Gibala Department
More informationThe oral meal or oral glucose tolerance test. Original Article Two-Hour Seven-Sample Oral Glucose Tolerance Test and Meal Protocol
Original Article Two-Hour Seven-Sample Oral Glucose Tolerance Test and Meal Protocol Minimal Model Assessment of -Cell Responsivity and Insulin Sensitivity in Nondiabetic Individuals Chiara Dalla Man,
More informationNITROGEN BALANCE AND LEUCINE KINETIC APPROACHES TO THE EXAMINATION OF PROTEIN REQUIREMENTS AND PROTEIN METABOLISM IN RESISTANCE ATHLETES
NITROGEN BALANCE AND LEUCINE KINETIC APPROACHES TO THE EXAMINATION OF PROTEIN REQUIREMENTS AND PROTEIN METABOLISM IN RESISTANCE ATHLETES By HARK A. TARNOPOLSKY, BPE., MD. A Thesis Submitted to the ~chool
More informationHuman Nutrition and Metabolism
Human Nutrition and Metabolism Supplementation with Aromatic Amino Acids Improves Leucine Kinetics but Not Aromatic Amino Acid Kinetics in Infants with Infection, Severe Malnutrition, and Edema 1,2 Marvin
More informationCharacteristics of skeletal muscle growth and protein turnover in a fast-growing rat strain
Br. J. Nutr. (1981), 46, I 7 Characteristics of skeletal muscle growth and protein turnover in a fast-growing rat strain BY P. C. BATES AND D. J. MILLWARD Clinical Nutrition and Metabolism Unit, Department
More informationReevaluation of the protein requirement in young men with the indicator amino acid oxidation technique 1 3
Reevaluation of the requirement in young men with the indicator amino acid oxidation technique 1 3 Mohammad A Humayun, Rajavel Elango, Ronald O Ball, and Paul B Pencharz ABSTRACT Background: The current
More informationMeasurement of muscle protein fractional synthesis and breakdown rates from a pulse tracer injection
Am J Physiol Endocrinol Metab 283: E753 E764, 2002. First published June 11, 2002; 10.1152/ajpendo.00053.2002. Measurement of muscle protein fractional synthesis and breakdown rates from a pulse tracer
More informationHuman Carbamylated LDL ELISA Kit (CBL-LDL Quantitation)
Product Manual Human Carbamylated LDL ELISA Kit (CBL-LDL Quantitation) Catalog Number MET-5032 96 assays FOR RESEARCH USE ONLY Not for use in diagnostic procedures Introduction Lipoproteins are submicroscopic
More informationEVALUATION OF THE OPTIMAL TRUE-ILEAL-DIGESTIBLE LYSINE AND THREONINE REQUIREMENT FOR NURSERY PIGS
Swine Day 2004 EVALUATION OF THE OPTIMAL TRUE-ILEAL-DIGESTIBLE LYSINE AND THREONINE REQUIREMENT FOR NURSERY PIGS N. A. Lenehan, M. D. Tokach, S. S. Dritz 1, J. L. Usry 2, R. D. Goodband J. M. DeRouchey,
More informationEffects of Trace Mineral Source on Growth and Mineral Balance in Yearling Horses
Effects of Trace Mineral Source on Growth and Mineral Balance in Yearling Horses T.L. Naile, S.R. Cooper, D.W. Freeman, and C.R. Krehbiel Story in Brief Sixteen yearling Quarter Horses were used in a split-plot
More informationDetermination of β2-agonists in Pork Using Agilent SampliQ SCX Solid-Phase Extraction Cartridges and Liquid Chromatography-Tandem Mass Spectrometry
Determination of β2-agonists in Pork Using Agilent SampliQ SCX Solid-Phase Extraction Cartridges and Liquid Chromatography-Tandem Mass Spectrometry Application Note Food Safety Authors Chenhao Zhai Agilent
More informationEffects of dietary Vitamin E level and source on sow, milk, and piglet concentrations of α- tocopherol
Kansas Agricultural Experiment Station Research Reports Volume 0 Issue 0 Swine Day (968-204) Article 268 202 Effects of dietary Vitamin E level and source on sow, milk, and piglet concentrations of α-
More informationAcute response of net muscle protein balance reflects 24-h balance after exercise and amino acid ingestion
Am J Physiol Endocrinol Metab 284: E76 E89, 2003. First published September 11, 2002; 10.1152/ajpendo.00234.2002. Acute response of net muscle protein balance reflects 24-h balance after exercise and amino
More informationPediatric Nutrition Care as a strategy to prevent hospital malnutrition. Div Pediatric Nutrition and Metabolic Diseases Dept of Child Health
Pediatric Nutrition Care as a strategy to prevent hospital malnutrition Div Pediatric Nutrition and Metabolic Diseases Dept of Child Health Child is not a miniature adult Specific for child growth and
More informationProtein Requirements of Healthy Pregnant Women during Early and Late Gestation Are Higher than Current Recommendations 1 4
The Journal of Nutrition Nutrient Requirements and Optimal Nutrition See corresponding commentary and article on pages 5 and 18. Protein Requirements of Healthy Pregnant Women during Early and Late Gestation
More informationNote: During 30 minute incubation; proceed thru appropriate sections below (e.g. sections II, III and V).
LEGEND MAX β Amyloid x 40 LEGEND MAX β Amyloid x 40 ELISA Kit Components and Protocol Kit Components Capture Antibody Coated Plate 1 stripwell plate 1 40 Standard (2) 20μg vial 5X Wash Buffer 125mL Standard
More informationCoingestion of whey protein and casein in a mixed meal: demonstration of a more sustained anabolic effect of casein
Am J Physiol Endocrinol Metab 303: E152 E162, 2012. First published May 8, 2012; doi:10.1152/ajpendo.00106.2012. Coingestion of whey protein and casein in a mixed meal: demonstration of a more sustained
More informationR. O. Gottlob, J. M. DeRouchey, M. D. Tokach, R. D. Goodband, J. L. Nelssen, S. S. Dritz 2, C. W. Hastad, K. R. Lawrence, and D. A.
Swine Day 2004 DETERMINATION OF THE APPARENT AND TRUE ILEAL AMINO ACID DIGESTIBILITY AND DIGESTIBLE AND METABOLIZABLE ENERGY OF SPECIALTY PROTEIN SOURCES INTENDED FOR NURSERY PIG DIETS 1 R. O. Gottlob,
More informationKey Words: Enzyme, Metabolizable Energy, Pigs
2000 Animal Science Research Report Effects of Hemicell Addition to Corn-Soybean Meal Diets on Energy and Nitrogen Balance in Growing Pigs Pages 117-122 L.A. Pettey, S.D. Carter and B.W. Senne Story in
More informationLatest developments in policy and research on the DIAASmethod to determine protein quality
Latest developments in policy and research on the DIAASmethod to determine protein quality Daniel Tomé AgroParisTech, INRA, France and Wageningen University, The Netherlands Event name Introduction The
More informationEffects of L-Carnitine in the Diet of Weanling Pigs II. Apparent Nutrient Digestibility, Whole Body Composition, and Tissue Accretion
Effects of L-Carnitine in the Diet of Weanling Pigs II. Apparent Nutrient Digestibility, Whole Body Composition, and Tissue Accretion M.J. Rincker, S.D. Carter, R.W. Fent, B.W. Senne, and K.Q. Owen Story
More informationNIH Public Access Author Manuscript J Nutr Health Aging. Author manuscript; available in PMC 2011 October 13.
NIH Public Access Author Manuscript Published in final edited form as: J Nutr Health Aging. 2002 ; 6(6): 358 362. ORAL AND INTRAVENOUSLY ADMINISTERED AMINO ACIDS PRODUCE SIMILAR EFFECTS ON MUSCLE PROTEIN
More information行政院國家科學委員會補助專題研究計畫成果報告
NSC892314B002270 898 1 907 31 9010 23 1 Molecular Study of Type III Hyperlipoproteinemia in Taiwan β β ε E Abstract β Type III hyperlipoproteinemia (type III HLP; familial dysbetalipoproteinemia ) is a
More informationEvaluation of Models to Estimate Urinary Nitrogen and Expected Milk Urea Nitrogen 1
J. Dairy Sci. 85:227 233 American Dairy Science Association, 2002. Evaluation of Models to Estimate Urinary Nitrogen and Expected Milk Urea Nitrogen 1 R. A. Kohn, K. F. Kalscheur, 2 and E. Russek-Cohen
More informationCombined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise
Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise René Koopman, Daphne L. E. Pannemans, Asker E. Jeukendrup, Annemie P. Gijsen, Joan M. G. Senden,
More informationAmino Acid Metabolism and Protein Requirements in Active, Adolescent. Males Using the Indicator Amino Acid Oxidation (IAAO) Technique
Amino Acid Metabolism and Protein Requirements in Active, Adolescent Males Using the Indicator Amino Acid Oxidation (IAAO) Technique by Jahmal Brooks A thesis submitted in conformity with the requirements
More informationPortsmouth, Hants. the true needs. Furthermore, the high cost of intravenous nutrition makes it that more important
Postgraduate Medical Journal (July 1975) 51, 441-445. A method of determining daily nitrogen requirements H. A. LEE B.Sc., M.B., B.S., F.R.C.P. T. F. HARTLEY B.Sc., Ph.D. Department of Nephrology, University
More informationExamination of lysine requirement of healthy young male adults on a Chinese habitual diet by the modified indicator amino acid oxidation method
Nutrition Research and Practice (Nutr Res Pract) 2014;8(1):59-65 http://dx.doi.org/10.4162/nrp.2014.8.1.59 pissn 1976457 eissn 2005-6168 Examination of lysine requirement of healthy young male adults on
More informationPhenylalanine. in cases of hyperphenylalaninemia and tetrahydrobiopterin deficiency
Evolving Methods for the Measurement of Phenylalanine A vital diagnostic marker and indicator for follow-up in cases of hyperphenylalaninemia and tetrahydrobiopterin deficiency Dr. Zoltan Lukacs Department
More informationPredicting Nutrient Requirements Based on Protein Deposition Rates
Predicting Nutrient Requirements Based on Protein Deposition Rates A FACTORIAL APPROACH TO PREDICTING ENERGY AND LYSINE REQUIREMENTS BASED ON WHOLE BODY PROTEIN DEPOSITION RATES Mark L. Lorschy and John
More informationSuppl. Table 1: CV of pooled lipoprotein fractions analysed by ESI-MS/MS
Supplement VLDL LDL HDL PC 3.3 1.77 1.3 LPC 4.82 2.5.35 SM 3.1 4.6 1.92 CER 2.17 6.3 4.15 PE 3.18 1.93 2.79 PE-pl 13.18 1.9 2.32 CE 2.9.65.4 FC.36 3.5 2.54 Suppl. Table 1: CV of pooled lipoprotein fractions
More informationMinimal Enteral Nutrition
Abstract Minimal Enteral Nutrition Although parenteral nutrition has been used widely in the management of sick very low birth weight infants, a smooth transition to the enteral route is most desirable.
More informationThe Effect of Varying Protein Quality and Energy Intake on the Nitrogen Metabolism of Parenterally Fed Very Low Birthweight (4600 g) Infants
Pediatr. Res. 15: 1040-1044 (1981) metabolism parenteral feeding nitrogen protein The Effect of Varying Protein Quality and Energy Intake on the Nitrogen Metabolism of Parenterally Fed Very Low Birthweight
More informationMammary Gland Metabolism of Amino Acids in the Lactating Sow: An In Vitro Study
Mammary Gland Metabolism of Amino Acids in the Lactating Sow: An In Vitro Study Walter L. Hurley, Professor, and Jane M. Bryson, Research Associate Department of Animal Sciences, University of Illinois,
More informationProtein Deposition in Growing and Finishing Pigs
1 Protein Deposition in Growing and Finishing Pigs DETERMINING WHOLE BODY PROTEIN DEPOSITION RATES IN PIGS. Mark L. Lorschy, Doug A. Gillis, John F. Patience and Kees de Lange. Summary There is controversy
More informationNEW METHODS FOR ASSESSING SUBSTRATE UTILIZATION IN HORSES DURING EXERCISE
R. J. Geor 73 NEW METHODS FOR ASSESSING SUBSTRATE UTILIZATION IN HORSES DURING EXERCISE RAYMOND J. GEOR The Ohio State University, Columbus, Ohio There are two major goals in designing diets and feeding
More informationOptimal Nutrition, Exercise, and Hormonal Therapy Promote Muscle Anabolism in the Elderly
EDUCATION Optimal Nutrition, Exercise, and Hormonal Therapy Promote Muscle Anabolism in the Elderly Robert R Wolfe, PhD Trauma, surgery, or other stress cause a catabolic loss of muscle mass. The clinical
More informationProduct Manual. Human LDLR ELISA Kit. Catalog Number. FOR RESEARCH USE ONLY Not for use in diagnostic procedures
Product Manual Human LDLR ELISA Kit Catalog Number STA-386 96 assays FOR RESEARCH USE ONLY Not for use in diagnostic procedures Introduction Cholesterol is an essential component of cellular membranes,
More informationThe art of tracing dietary fat in humans. Leanne Hodson
The art of tracing dietary fat in humans Leanne Hodson Dietary fat Other lipoproteins: IDL, LDL, HDL Hodson and Fielding linical Lipidology (2010) Relationship between blood & dietary fatty acids Typically:
More informationTHE RESPONSE OF skeletal muscle in critical illness is
0013-7227/02/$15.00/0 The Journal of Clinical Endocrinology & Metabolism 87(7):3378 3384 Printed in U.S.A. Copyright 2002 by The Endocrine Society Inverse Regulation of Protein Turnover and Amino Acid
More informationDetermination of 6-Chloropicolinic Acid (6-CPA) in Crops by Liquid Chromatography with Tandem Mass Spectrometry Detection. EPL-BAS Method No.
Page 1 of 10 Determination of 6-Chloropicolinic Acid (6-CPA) in Crops by Liquid Chromatography with Tandem Mass Spectrometry Detection EPL-BAS Method No. 205G881B Method Summary: Residues of 6-CPA are
More informationIsoleucine requirement of pregnant sows 1
Published November 25, 2014 Isoleucine requirement of pregnant sows 1 D. J. Franco,* J. K. Josephson,* S. Moehn,* P. B. Pencharz, and R. O. Ball* 2 *Department of Agriculture, Food and Nutritional Sciences,
More informationGoals. Goals. Maintenance Rations 4/25/2014. Week 4 Lecture 12. Clair Thunes, PhD
Maintenance Rations Week 4 Lecture 12 Clair Thunes, PhD Animal Science 126 Equine Nutrition Goals Understand that in reality that horses have an amino acid requirement not a CP requirement That there are
More informationUNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DIVISION OF BASIC MEDICAL SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY
1 UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DIVISION OF BASIC MEDICAL SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY GLUCOSE HOMEOSTASIS An Overview WHAT IS HOMEOSTASIS? Homeostasis
More informationADC Online First, published on June 14, 2011 as /adc Original article
ADC Online First, published on June 14, 2011 as 10.1136/adc.2010.185637 Original article Appendices 1 4 are available online only. To view these fi les please visit the journal online (http://adc.bmjgroup.com)
More informationAntoine Bouchoux, Pierre-Emerson Cayemitte, Julien Jardin, Geneviève Gésan-Guiziou, and Bernard Cabane
Biophysical Journal, Volume 96 Supplementary Material Casein Micelle Dispersions under Osmotic Stress Antoine Bouchoux, Pierre-Emerson Cayemitte, Julien Jardin, Geneviève Gésan-Guiziou, and Bernard Cabane
More informationAMERICAN ACADEMY OF PEDIATRICS. New Developments in Hyperphenylalaninemia. Committee on Nutrition
AMERICAN ACADEMY OF PEDIATRICS Committee on Nutrition New Developments in Hyperphenylalaninemia In recent years it has become apparent that hyperphenylalaninemia in newborn infants may be caused by a variety
More informationESPEN Congress Vienna Nutritional implications of renal replacement therapy in ICU Nutritional support - how much nitrogen? W.
ESPEN Congress Vienna 2009 Nutritional implications of renal replacement therapy in ICU Nutritional support - how much nitrogen? W. Druml (Austria) Nutritional Implications of Renal Replacement Therapy
More informationindicator amino acid oxidation, older female adults, phenylalanine oxidation, protein requirement,
The Journal of Nutrition Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions See corresponding commentary and article on pages 5 and 73. Dietary Protein Requirement of Female Adults >65
More informationChapter 2 Transport Systems
Chapter 2 Transport Systems The plasma membrane is a selectively permeable barrier between the cell and the extracellular environment. It permeability properties ensure that essential molecules such as
More informationThe Order of Limiting Amino Acids in Ladino Clover Leaf Protein Concentrate Fed to Chicks
227 The Order of Limiting Amino Acids in Ladino Clover Leaf Protein Concentrate Fed to Chicks Hiroshi UEDA and Mitsuaki OHSHIMA Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa-ken 761-07 From
More informationNovel Quantitative Tools for Engineering Analysis of Hepatocyte Cultures used in Bioartificial Liver Systems
Noel Quantitatie Tools for Engineering Analysis of Hepatocyte Cultures used in Bioartificial Lier Systems M. Ierapetritou *, N. Sharma and M. L. Yarmush Department of Chemical & Biochemical Engineering
More informationApplication Note. Author. Abstract. Introduction. Food Safety
Determination of β2-agonists in Pork with SPE eanup and LC-MS/MS Detection Using Agilent BondElut PCX Solid-Phase Extraction Cartridges, Agilent Poroshell 120 column and Liquid Chromatography-Tandem Mass
More informationQuantitative Analysis of Underivatized Amino Acids in Plant Matrix by Hydrophilic Interaction Chromatography (HILIC) with LC/MS Detection
Application Note Food Testing, Metabolomics, Agricultural Chemistry, Environmental Quantitative Analysis of Underivatized Amino Acids in Plant Matrix by Hydrophilic Interaction Chromatography (HILIC) with
More informationsynthesis in vivo to insulin
Biochem. J. (1988) 254, 579-584 (Printed in Great Britain) Amino acid infusion increases the sensitivity of muscle protein synthesis in vivo to insulin Effect of branched-chain amino acids 579 Peter J.
More informationEFFECT OF DIETARY CATION-ANION DIFFERENCE ON MINERAL BALANCE IN WEANLING HORSES. Authors:
EFFECT OF DIETARY CATION-ANION DIFFERENCE ON MINERAL BALANCE IN WEANLING HORSES 1999 Animal Science Research Report Authors: Story in Brief Pages 182-188 S.R. Cooper, D.R. Topliff, D.W. Freeman, J.E. Breazile
More informationAll stocks and calibration levels were prepared in water: methanol (50:50) v/v to cover range of all steroid concentrations (refer Table 1).
Application LCMS-8040 Simultaneous determination of 11 steroids and Vitamin D2/D3 in human serum using LC/MS/MS - Introduction Quantification of endogenous hormonal steroids and their precursors is essential
More informationSymposium: Nutritional Implications of Dietary Protein Restriction in Diabetes Mellitus
Symposium: Nutritional Implications of Dietary Protein Restriction in Diabetes Mellitus Fed State Protein Metabolism in Diabetes Mellitus 1 Pierpaolo De Feo Department of Internal Medicine, Endocrine and
More informationEffect of Enteral Versus Parenteral Feeding on Leucine Kinetics and Fuel Utilization in Premature Newborns
003 1-399819413604-0429$03.00/0 PEDIATRIC RESEARCH Copyright Q 1994 International Pediatric Research Foundation, Inc. Vol. 36, No. 4, 1994 Printed in (I. S.A. Effect of Enteral Versus Parenteral Feeding
More informationDetermination of Amantadine Residues in Chicken by LCMS-8040
Liquid Chromatography Mass Spectrometry Determination of Amantadine Residues in Chicken by LCMS-8040 A method for the determination of amantadine in chicken was established using Shimadzu Triple Quadrupole
More informationIntradialytic Parenteral Nutrition in Hemodialysis Patients. Hamdy Amin, Pharm.D., MBA, BCNSP Riyadh, Saudi Arabia
Intradialytic Parenteral Nutrition in Hemodialysis Patients Hamdy Amin, Pharm.D., MBA, BCNSP Riyadh, Saudi Arabia Disclosure Information Intradialytic Parenteral Nutrition in Hemodialysis Patients Hamdy
More informationEffect of Excess of Individual Essential Amino Acids in Diets on Chicks
135 Effect of Excess of Individual Essential Amino Acids in Diets on Chicks Jun-ichi OKUMURA and Kiyoto YAMAGUCHI Laboratory of Animal Nutrition, Faculty of Agriculture, Nagoya University, Nagoya-shi 464
More informationEnergy and Nitrogen Balance of Pigs Fed Four Corn Grains
Energy and Nitrogen Balance of Pigs Fed Four Corn Grains R.W. Fent, S.D. Carter, M.J. Rincker, and J.S. Park Story in Brief Because corn is the primary energy source in diets for pigs, any variability
More informationFluorescent Carbon Dots as Off-On Nanosensor for Ascorbic Acid
Electronic Supplementary Material (ESI) for RSC Advances. This journal is The Royal Society of Chemistry 2014 Fluorescent Carbon Dots as Off-On Nanosensor for Ascorbic Acid Jun Gong, Xin Lu, Xueqin An*
More informationEffects of Dietary Standardized Ileal Digestible Isoleucine:Lysine Ratio on Nursery Pig Performance
Kansas Agricultural Experiment Station Research Reports Volume 2 Issue 8 Swine Day Article 12 January 2016 Effects of Dietary Standardized Ileal Digestible Isoleucine:Lysine Ratio on Nursery Pig Performance
More informationGlutamine Kit. For the determination of glutamine and glutamate in human EDTA plasma and serum. For research use only K 7732.
Li StarFish S.r.l. Via Cavour, 35-20063 Cernusco S/N (MI), Italy Tel. +39-02-92150794 - Fax. +39-02-92157285 info@listarfish.it -www.listarfish.it Manual Kit For the determination of glutamine and glutamate
More informationIMPACT OF DIETARY SALT CONCENTRATION ON WATER INTAKE AND PHYSIOLOGICAL MEASUREMENTS OF FEEDLOT CATTLE. Authors:
IMPACT OF DIETARY SALT CONCENTRATION ON WATER INTAKE AND PHYSIOLOGICAL MEASUREMENTS OF FEEDLOT CATTLE 1999 Animal Science Research Report Authors: Story in Brief Pages 159-164 A.F. La Manna, F.N. Owens,
More informationWhat systems are involved in homeostatic regulation (give an example)?
1 UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DIVISION OF BASIC MEDICAL SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY GLUCOSE HOMEOSTASIS (Diabetes Mellitus Part 1): An Overview
More informationDetermination of Bath Salts (Pyrovalerone Analogs) in Biological Samples
Determination of Bath Salts (Pyrovalerone Analogs) in Biological Samples Application Note Forensic Toxicology Authors Joe Crifasi Saint Louis University Forensic Toxicology Laboratory Saint Louis, Mo.
More informationO O H. Robert S. Plumb and Paul D. Rainville Waters Corporation, Milford, MA, U.S. INTRODUCTION EXPERIMENTAL. LC /MS conditions
Simplifying Qual/Quan Analysis in Discovery DMPK using UPLC and Xevo TQ MS Robert S. Plumb and Paul D. Rainville Waters Corporation, Milford, MA, U.S. INTRODUCTION The determination of the drug metabolism
More informationSupplement: Protein Metabolism in Response to Ingestion Pattern and Composition of Proteins
Supplement: Protein Metabolism in Response to Ingestion Pattern and Composition of Proteins Regulation of Muscle Protein by Amino Acids 1,2 Robert R. Wolfe 3 University of Texas Medical Branch and Shriners
More information