MATHEMATICAL MODEL FOR ALTERED SECRETION OF GROWTH HORMONE

Transcription

1 MATHEMATICAL MODEL FOR ALTERED SECRETION OF GROWTH HORMONE Dr. Geetha.T 1, Ananthi.N 2 1 Assistant Professor of Mathematics K.N. Government Arts College for women Thanjavur, Tamil Nadu, South India 2 Assistant Professor, R.V.S. College of Engineering and Technology, Karaikal, U.T. of Puducherry. South India ABSTRACT In this paper the steady state availability of human hormone with time for stress effect and recoveries and also found TTP for GH that are generally distributed availability bounds are used in human hormone due to stress effect. Keywords : hormone pulsatility, insulin-like growth factor-i, soldiers, leptin, Testosterone, gh, ctmc, emc mttf. 1. Introduction The pulsatile release of growth hormone (GH) and luteinizing hormone (LH) from the ante rior pituitary gland is integral for signaling secretion of insulin-like growth factor (IGF)-I and testosterone, respectively. GH and LH pulse number were unaffected. Because GH and LH positively regulate IGF-I and testosterone, these data imply that the physiological strain induced a certain degree of peripheral resistance. During periods of energy deficiency, amplitude modulation of GH and LH pulses may precede alterations in pulse numbers. THE ENDOCRINE RESPONSE TO sustained physical exertion superimposed on caloric and sleep restriction serves to provide adequate fuels to meet metabolic needs for such physiological processes as tissue repair, regeneration, and recovery. The pulsatile release of GH and LH from the anterior pituitary gland is integral for the trophic effects that these hormones exert on IGF-I and testoserone, respectively. The manner in which anterior pituitary hormones are released and delivered to target tissues is more biologically significant than the overall mean hormonal concentratio ns was well. Because of the episodic release pattern of GH and LH, multiple time-point measures are necessary to fully characterize the trophic effects these hormones may have. Although alterations in IGF-I and testosterone are known to be mediated by fluctuations in GH and LH, The purpose of the present study was to further characterize the physiological consequences of short -term military operational stress on the secretory patterns of GH and LH release as analyzed by deconvolution algorithms by obtaining serial blood samples (every 20 min) drawn for 12 h overnight from soldiers before and after 4 days of military operational stress. The level of caloric restriction, sleep deprivation, and prolonged work were chosen to model current real-world scenarios expected by the United States military in high-intensity combat situations. In addition, we concomitantly measured the downstream anabolic mediators of these signaling peptides: testosterone and IGF -I, IGF binding proteins (BPs)-1 and -3, and other metabolic markers (i.e., leptin, free fatty acids, and glucose). Although prior pulsatility programs (i.e., Pulsar, etc.) were limited in that they provided only descriptive information about hormone concentration peaks, recent advances in time series software analysis now allow accurate determination of underlying glandular hormonal secretion rate and half-life from measurements obtained from the systemic circulation. A unique paradigm in which to study endocrine responses to metabolic stress. Soldiers, analog ous to emergency rescue personnel (i.e., wildlife firefighters, medical response teams, etc.) and ultra endurance athletes (i.e, cyclists during the Tour de France, participants in the Eco challenge, etc.), are often required to perform heavy sustained phy sical exertion in the face of nutritional and sleep deprivation. The purpose of the present study was to further characterize the physiological consequences of short -term military operational stress on the secretory patterns of GH and LH release as analyze d by deconvolution algorithms by obtaining Impact Factor ( GIF) 5.42 Page 23

2 serial blood samples (every 20 min) drawn for 12 h overnight from soldiers before and after 4 days of military operational stress. An algorithm searched for significant increases and decreases among data points in a series via pooled t-tests. Two points were used for the determination of a peak and one point to establish a nadir. A peak was defined as a series of concentrations that demonstrated an increase over time followed by a decrease, with the additional requ irement that a nadir (i.e., a decrease followed by an increase) was present on each side of the peak Mean GH concentration was significantly increased after military stress compared with the control condition. The increase in mean GH concentration was accompanied by an increase in the following secretion parameters: area under bursts, amplitude of bursts, basal secretion rate, overnight basal secretion, overnight pulsatile secretion, and total overnight secretion. GH half-life, number of bursts, interval between bursts, and amplitude of largest burst were similar between the control and military operational stress conditions. Fig.1. Insulin-like growth factor (IGF)-I system responses during the control and military stress week measured bi-hourly from 1800 to A: total IGF-I. B: free IGF-I. C: IGF binding protein (BP)-1. D: IGFBP Mathematical Model Availability bounds are stress effect information about the distribution also investigated are applicability of convenient exponential models in evaluating availability for human body that have two sided bounded distribution of times to planned outages. A general closed-form formula is derived for the steady-state availability of a human body with multiple outage types of arbitrary distributions. The formula shows that only the mean values of times due to stress effect (TTR i,i = n) affect the steady-state availability; i.e., distributions of TTR with the same mean value have the same effect in determining the steady-state human body availability. However, the distributions of times to outages, (TTO i,i = n), have an important impact on the steady-state human body availability. Bounds are provided for the steadystate availability for a human body subject to unplanned outages, for which times-to-outages are exponentially distributed and planned outages for which times-to-outages have bounded distributions. The steady-state availability of the system in this section can be obtained from the general formula (12). The result in summarized in theorem 1. Theorem 1: The steady-state availability of a system with unplanned and planned outages is: Impact Factor ( GIF) 5.42 Page 24

3 Theorem 1 shows that any distribution G(x) of TTU with the same MTTU = 2-1, results in the same steady-state system availability (given that other parameters are fixed). However, the distribution of TTP does affect system availability through ( ), in which ( ) is the Laplace Stieltjes transform of TTP evaluated at S = (1) (2) Because is a positive real number, then ( ) can be interpreted as Pr{a planned outage occurs when the system is in the working state}. The complementary probability,1 - ( ), is Pr{working system has an unplanned outage}. The ( ) has the properties: 1. if 1 > 2 > 0, then ( 1 ) < ( 2 ): ( ) is a monotonically decreasing function. 2. (0) =1, ( ) =0, 0 ( ) 1. It follows that ( ) is also a monotonically decreasing functions of. Formula for different distributions Before deriving the availability bound, derive availability formulae for specific distr ibutions of TTP: 1) deterministic, 2) exponentially distributed, and 3) uniformly distributed. TTP is Deterministic Let TTP = T then the above equation becomes TTP is exponentially distributed. Let (3) (4) Impact Factor ( GIF) 5.42 Page 25 (5)

4 total IGF - 1 International Journal of World Research, Vol: I Issue XXXV, April 2017, Print ISSN: X TTP is uniformly distributed on [T 1, T 2 ], (0 < T 1 < T 2 < 0) 3. Results : Case T n ( ) (6) hours Fig. 2. total IGF-I 4. Conclusion Our results demonstrate that brief periods of intensive physical activity superimposed on energy and sleep restriction induced amplifications in GH and LH secretion, yet at the same time resulted in decreases in hormones that these signaling peptides are responsible for stimulating, namely IGF-I and testosterone. That short-term military operational stress can exert marked effects in neuroendocrine secretion patterns raises important questions concerning the potential adverse effects on longer-term military operational stress on underlying physiology and metabolism and the health status of military personnel 5. Reference 1. Bradley C. Nindl,1 Kevin R. Rarick,1 John W. Castellani, Alexander P. Tuckow, John F. Patton, Andrew J. Young, and Scott J. Montain, Altered secretion of growth hormone and luteinizing hormone after 84 h of sustained physical exertion superimposed on caloric and sleep restriction, J Appl Physiol 100: , Yonghuan Cao, Hairong Sun, Kishor S. Trivedi, and James J. Han, System Availability With Non-Exponentially Distributed Outages, IEEE transactions on reliability, 51:2, Chan JL, Heist K, DePaoli AM, Veldhuis JD, and Mantzoros CS. The role of falling leptin levels in the neuroendocrine and metabolic adaptation to short-term starvation in healthy men. J Clin Invest 111: , Dallman MF, Akana SF, Bhatnagar S, Bell ME, Choi S, Chu A, Horsley C, Levin N, Meijer O, Soriano LR, Strack AM, and Viau V. Starvation: early signals, sensors, and sequelae. Endocrinology 140: , Impact Factor ( GIF) 5.42 Page 26

5 5. Lado-Abeal J, Veldhuis JD, and Norman RL. Glucose relays information regarding nutritional status to the neural circuits that control the somatotropic, corticotropic, and gonadotropic axes in adult male rhesus macaques. Endocrinology 143: , Hartman ML, Veldhuis JD, Johnson ML, Lee MM, Alberti KGMM, Samojlik E, and Thorner MO. Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men. J Clin Endocrinol Metab 74: , Ho KY, Veldhuis JD, Johnson ML, Furlanetto R, Evans WS, Alberti KGMM, and Thorner M. Fasting enhances growth hormone secretion and amplifies the complex rhythms of growth hormone secretion in man. J Clin Invest 81: , Oster MH, Fielder PJ, Levin N, and Cronin MJ. Adaptation of the growth hormone and insulin-like growth factor-i axis to chronic and severe calorie or protein malnutrition. J Clin Invest 95: , Veldhuis JD, Carlson ML, and Johnson ML. The pituitary gland secretes in bursts: appraising the nature of glandular secretory impulses by simultaneous multiple-parameter deconvolution of plasma hormone concentrations Proc Natl Acad Sci USA 84: , K. S. Trivedi, Probability and Statistics with Reliability, Queueing, and Computer Science Applications, 2nd ed. New York: Wiley, V. G. Kulkarni, Modeling and Analysis of Stochastic Systems: Chapman & Hall, M. Perman, A. Senegacnik, and M. Tuma, Semi-Markov models with an application to power-plant reliability analysis, IEEE Trans. Reliability, vol. 46, pp , Impact Factor ( GIF) 5.42 Page 27