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1 Hormonlaboratorium der Universitätsfrauenklinik, Zurich, Switzerland THE RENAL CLEARANCE OF FOLLICLE-STIMULATING AND LUTEINIZING HORMONE IN POSTMENOPAUSAL WOMEN By Paul J. Keller ABSTRACT The renal clearance of follicle-stimulating and luteinizing hormone (FSH, LH) was studied in seven postmenopausal women. The clearance values for FSH ranged from 0.16 to 0.70 (mean 0.58) ml/min, and those for LH from 0.03 to 0.26 (mean 0.14) ml/min. Thus the mean FSH clearance was 4.1 times greater than the LH clearance. The difference was statistically confirmed by the Wilcoxon test. Similarly the mean FSH/LH ratio was four times higher in urine than in plasma when results were expressed in terms of NIH-FSH-S2 and NIH\x=req-\ LH-S3, or in terms of the 2nd International Reference Preparation for Human Menopausal Gonadotrophin. Consequently, the plasma contained relatively more LH than the corresponding urine samples. A nonspecific effect of plasma proteins on the bioassay of FSH and LH was excluded. Interest in the relationship between follicle-stimulating hormone (FSH) and luteinizing hormone (LH) has considerably increased during recent years. However, our knowledge on the behaviour of FSH and LH in physiological and pathological conditions is essentially based on studies of urinary extracts. The problem of the renal clearance of the two hormones has not yet been investigated sufficiently to decide whether these data may be considered as relevant to the conditions in the human body. The present study was thus carried out, involving the simultaneous deter mination of FSH and LH in individual plasma and urine samples of post menopausal women as well as the resulting renal clearance of these hor mones.

2 MATERIALS AND METHODS 1. Plasma and Urine 7 healthy postmenopausal women, aged from 50 to 62 years volunteered for this study. None of the subjects received hormonal therapy. The renal function, as judged by case history, albumen and sediment was normal. From each subject a complete 48-hour urine was collected. The urine was stored in a cool place during the col lection and processed immediately on arrival in the laboratory. 24 hours aer starting the collection, ml of citrated blood were obtained from each woman. The blood was centrifuged and the plasma collected and processed immediately. The plasma samples ranged from 90 to 130 ml. 2. Extraction The urine was extracted according to the method of Albert (1955) as described previously (Keller 1963). The moist acetone precipitate was further purified with 10 /o ammonium acetate in 70 /o ethanol, followed by reprecipitation of the active material with absolute ethanol saturated with ammonium acetate (Albert et al b). The final extracts were washed with absolute ethanol and anhydrous ether, dried over CaCL and stored at -20 C. The weight of the extracts ranged from 3.1 to 7.4 mg per 24 hours of urine. The plasma was extracted as described previously (Keller Sc Rosemberg 1965). The weight of the powders ranged from 8 to 17 mg per ml of original plasma. For bio assay, both extracts were dissolved in appropriate volumes of physiological saline. 3. Bioassay Follicle-stimulating hormone (FSH) was determined by means of the ovarian aug mentation reaction (AR) in immature female rats treated with 20 IU of human chorionic gonadotrophin (HCG) as described by Steelman Sc Pohley (1953). Luteinizing hormone (LH) was estimated by means of the four-hour modification of the ovarian ascorbic acid depletion test (OAAD) in immature, pseudopregnant rats as described by Parlow (1958). Controls were used in all experiments. As far as possible, the tests were performed as 4-point assays; due to the scarcity of material, some experiments had to be carried out as 3-point assays. 2 and 4 hour-equivalents of urine and 12 to 24 ml-equivalents of plasma were administered per animal in the AR, 1 and 3 hour-equivalents of urine and 4 to 12 ml-equivalents of plasma in the OAAD assay. 3 to 5 animals were used for each dose. 4. Standards The 2nd International Reference Preparation for Human Menopausal Gonadotrophin (2nd IRP, 40 IU FSH or LH per ampoule) and NIH-FSH-S-2 or NIH-LH-S3 were used simultaneously as standards. Results were calculated in terms of IU FSH or LH, or as milligram-equivalents (mg-eq.) of the NIH standards. 5. Statistics Statistical calculations were performed as recommended by Borth et al. (1957). The significance of pair-differences was tested by means of the Wilcoxon test as described in Geigy's Scientific Tables.

3 A. FSH and LH Activity of Individual Postmenopausal Urine The excretion of FSH in the urine ranged from (mean 130) IU or (mean 5.7) mg-eq. NIH-FSH-S2 per 24 hours. The concentration per litre urine was (mean 170) IU or (mean 7.7) mg-eq. NIH- FSH-S2. The excretion of LH in urine was (mean 28) IU or (mean 0.10) mg-eq. NIH-LH-S3 per 24 hours; the concentration per litre urine was (mean 39) IU or (mean 0.14) mg-eq. NIH-LH-S3 (Table 1). Hence the FSH/LH ratio in urine ranged from when calculated in terms of the 2nd IRP and from when calculated in terms of the NIHstandards. The mean ratio was 4.5 and 59 respectively. All 4-point assays were valid with regard to parallelism. The precision was satisfactory; the mean value was 0.14 (range ) in the AR, and 0.21 (range ) in the OAAD assay. B. FSH and LH Activity in Individual Postmenopausal Plasma Samples The FSH activity in the individual plasma samples ranged from (mean 140) IU or (mean 6.4) mg-eq. NIH-FSH-S» per litre. The LH activity was (mean 150) IU or (mean 0.52) mg-eq. NIH- LH-S3 per litre. The FSH/LH ratio equaled in terms of the 2nd IRP and in terms of the NfH-standards. The mean ratio values were 1.1 and 14 respectively (Table 1). No significant deviation from parallelism was observed in any of the 4- point assays. The mean index of precision was 0.10 (range ) in the AR, and 0.24 (range ) in the OAAD assay. C. Renal Clearance of FSH and LH The renal clearance of FSH and LH was calculated according to the formula VCu/Cp, where Cu is the concentration of the hormones in the urine, Cp the concentration in plasma and V the excretion rate of urine in ml/min. Results as ml/min. were expressed The clearance values for FSH ranged from (mean 0.58) ml/min, those for LH from (mean 0.14) ml/min (Table 1). Consequently the mean FSH clearance was 4.1 times greater than the LH clearance. This ob servation was confirmed statistically by means of the Wilcoxon test. The mean difference between the individual FSH and LH clearance values was significantly different from zero; the probability of chance occurrence was 0.02.

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6 Table 2. Effect of plasma extracts on FSH and LH activity of human menopausal gonadotrophin. End point Preparation Doses per animal standard (mg) plasma extract (ml-equivalents) Relative potency of standard and plasma extract in terms of standard (Confidence limits, = 0.95) AR Pergonal 23 OAAD Pergonal 23 OAAD HMG-Z» 0.2 ; ; ; ;6 6 ; 18 2 ; ( ) 1.1 ( ) 0.99 ( ) * Laboratory standard, extracted from pooled menopausal urine according to the method of Albert (1955). End points: AR: Ovarian augmentation reaction in HCG-treated rats. OAAD: Ovarian ascorbic acid depletion. Assay design, 2 and 2. Number of animals, per assay. D. Effect of Nonspecific Factors on the Estimation of FSH and LH in Plasma Differences in FSH and LH activity in urine and plasma could easily be caused by nonspecific augmentation or inhibitory factors of inert material. Hence the effect of extremely low titered plasma extracts from a 25 years old amenorrhoic woman on FSH and LH activity of postmenopausal urine was investigated. Comparable doses of the»inert«material were added to the known amounts of urinary gonadotrophins (Pergonal 23 and HMG-Z, a labo ratory standard obtained from postmenopausal urine) and the mixtures tested against the original standards in the AR and OAAD system. The results are summarized in Table 2. Apparently neither the FSH nor the LH activity were changed significantly by the added plasma extracts. DISCUSSION The renal clearance of human chorionic gonadotrophin (HCG) and»total«gonadotrophic activity of pituitary origin has been studied previously by several authors (Loraine 1950; Johnson et al. 1950; Apostolakis Se Loraine

7 1960). So far, however, no data are available on the renal clearance of fol licle-stimulating and luteinizing hormone. The investigation of these problems seems to be highly important, as most studies on FSH and LH are based on results obtained in urine. Hence the FSH/LH ratios in urine and plasma samples of seven postmeno pausal women were studied. In all subjects there was a considerable dif ference in this proportion in as far as the plasma contained relatively more LH than the urine. The mean FSH/LH ratio was four times lower in plasma than in urine. Similar results were found by Albert (1963), when the FSH/LH ratios in extracts of postmenopausal urine and of human pituitary glands were compared. Pituitary extracts contained relatively more LH; the FSH/LH ratio was 0.5, when calculated in terms of NÎH-FSH-S. and NIH-LH-S.. In urinary extracts the ratio was 2.5. As the mean renal clearance values in the present study were 0.57 ml/min for FSH and 0.14 ml/min for LH, the dis crepancy between the two ratios seems to be due to renal factors rather than to different secretion rates of the two hormones by the pituitary gland. Studies of this type are hampered by many problems, mainly because a direct comparison between two biological fluids is necessary. In the present investigation the extraction method of Albert (1955) and a purification step by means of 10% ammonium, acetate in 70 fl/o ethanol (Albert 1961 ) was used for urine, and the method of Keller Se Rosemberg (1965), which involves extraction with the same reagent, for plasma. In previous studies, the mean recoveries of these procedures were found to be 89 /o (Rosemberg Sc Keller 1965) and 87 /o (Keller Sc Rosemberg 1965) respectively, at least when measured as»total«gonadotrophic activity. Consequently the assumption of approximately equal yields for the calculation of the renal clearance seemed to be justified. The question whether the proportion of FSH and LH is changed by any of these extraction methods, is extremely difiicult to decide. Actually it is almost impossible to determine the FSH/LH ratio of untreated urine or plasma. However, there is indirect evidence that the two methods do not alter this ratio considerably (Albert et al a; Keller 1966). Changes in the proportion of FSH and LH could be due to nonspecific factors, such as augmentation or inhibitory effects of plasma proteins in the bioassay. Consequently the effect of low-titered plasma extracts on FSH and LH activity of urinary gonadotrophins was studied by the AR and OAAD assay respectively. No significant effect could be demonstrated in any of these assays. Thus the present results seem to be reliable. It is of interest to note that the renal clearances of LH measured in the OAAD system and of»total«gonadotrophic activity measured by the mouse uterine weight assay are very similar. Apostolakis Sc Loraine (1960), using this assay, found a mean value

8 of 0.17 for LH was 0.14 ml/min. The renal clearance of FSH was more similar to et al. ml/min for»total«gonadotrophic activity, whereas our mean value the clearance of exogenous menopausal gonadotrophins. Apostolakis (1961) determined the»total«gonadotrophic clearance of parenterally ad ministered pituitary extracts. The values ranged from ml/min. Our mean value for the renal clearance of endogenous FSH was 0.58 ml/min. It is surprising that the renal clearance of HCG, which is biologically as well as immunologically in many ways similar to LH, is apparently much higher. Loraine (1950) found a mean value of 0.95 ml/min, and Johnson et al. (1950) of 0.42 ml/min. The FSH/LH ratio in the urine of different subjects seemed to be variable. However, there were no means of testing the statistical significance of this observation. The same statement applies to the plasma. The ratio was about 13 times higher, when calculated in terms of ovine pituitary standards (NIH- FSH/NIH-LH) instead of human urinary standards (2nd ÍRP). This phenomen has been studied and discussed previously (Rosemberg et al. 1964; Keller 1966). The present findings, i. e. the comparatively low clearance of LH, will have to be taken into consideration in future studies on the excretion of FSH dis and LH. Changes in the FSH/LH ratio in urine may well be due to a similar disposal of these hormones by the kidney rather than to differences in the pituitary secretion rate. ACKNOWLEDGEMENTS I am indebted to Prof. E. Held, Zurich, for his continuous interest and encouragement, to Dr. D. R. Bangham, London, for a supply of the 2nd International Reference Pre paration for Human Menopausal Gonadotrophin, to Dr. E. Rosemberg, Worcester, Mass., for providing NIH-FSH-Sg and NIH-LH-S3, and to Dr. Th. Reich, Zurich, for help in the statistical analysis. Particular thanks are due to my wife, Mrs. R. Keller, for her indefatigable help and skilled technical assistance. REFERENCES Albert.: Proc. Mayo Clin. 30 (1955) 552. Albert.: Proc. 5th Pan Am. Congress of Endocrinology (1963) 17. Albert.. Kobi J.. Leiferman J. Se Dernier!.: J. clin. Endocr. 21 (1901 a) 1. Albert., Stellmacher V. Sc Leiferman J.: J. clin. Endocr. 21 (1961 b) 856. Apostolakis M. Sc Loraine J..: J. clin. Endocr. 20 (1960) Apostolakis M.. Nowakowski H. Sc Voigt K. D.: J. clin. Endocr. 21 (1961) 575. Borth R., Diczfalusy E. Sc Heinrichs H. D.: Arch. Gynäk. 188 (1957) 497. Johnson S. G.. Albert A. Se Wilson R. B.: J. clin. Endocr. 10 (1950) 371. Keller P. ].: Gynaecologia (Basel) 756 (1963) 380.

9 Keller P. J.: Acta endocr. (Kbh.) 52 (1966) 348. Keller P. J. Sc Rosemberg,.. J. clin. Endocr. 25 (1965) Loraine J..: Quart. J. exp. Physiol. 36 (1950) 11. Parlow A. F.: Fed. Proc. 17 (1958) 402. Rosemberg E. Sc Keller P. J.: J. clin. Endocr. 25 (1965) Rosemberg E., Solod E. A. Sc Albert.: J. clin. Endocr. 24 (1964) 714. Steelman S. L. Sc Pohley F. M.: Endocrinology 53 (1953) 604. Received on April 28th, 1966.

Follicle-Stimulating Hormone (FSH) and Luteinzing

The Journal of Clinical Invest'gaio* Vol. 46, No. 12, 1967 Follicle-Stimulating Hormone (FSH) and Luteinzing Hormone (LH) in the Urine of Prepubertal Children * ARLEEN B. RIFKIND, HOWARD E. KULIN, AND