Investigating the effect of a resistance training session on growth hormone response in male athletes and non-athletes

Dissertation for Master's Degree in Sports Physiology

Abstract

Growth hormone binding proteins with high absorption are converted by different mechanisms depending on the species.

The purpose of this research is to investigate the effect of a session of stimulating activity resistance to the growth hormone response in male athletes and non-athletes.

The current research is semi-experimental and pre-test, post-test.

The subjects included 10 male athletes and 10 non-athletic males in the age group of 25-35 years old. An exercise that included chest press, knee extension, underarm rowing and knee bending was used. SPSS 18 software was also used for data collection. The findings showed that there is a significant difference between the amount of growth hormone of the athletes during different periods of time, so that the amount of growth hormone increased significantly in response to resistance training immediately, 20 minutes, 40 minutes, 60 minutes after the training compared to the pre-test. These findings are also true for non-athletes.

1-1 Introduction

Growth hormone [1] (somatotropin) is secreted by somatotrophs, which includes a major part of the anterior pituitary structure. Growth hormone in humans is a polypeptide chain with 191 amino acids with two interchain disulfide bonds. The half-life of GH hormone in plasma is 20 to 30 minutes. This hormone is released in bursts or pulses and 4 to 8 bursts in the body. The release time of this hormone is after eating and during exercise and sleep. GH hormone increases significantly during growth and puberty, and this increase in secretion continues during adulthood. The lack of GH in the body causes short stature and its increase also causes giantism. The important point is that GH does not directly affect growth, but acts by stimulating the formation of other hormones. The main hormones affected by GH are called insulin-like growth factors (IGF[2]) and IGF-1 is the most important somatomedin during postnatal development. The half-life of IGF-1 in the body is between 3 and 18 hours due to the presence of binding proteins. The structure of IGF-1 is similar to proinsulin and is called insulin-like. The secretion of IGF-1 decreases with malnutrition in the body. Some amino acids, such as arginine, are strong stimulators of GH secretion in the body, and in contrast to increasing blood sugar, it inhibits GH secretion. Generally, GH deficiency causes obesity in children and increases fat in adults. The way growth hormone is released in physiological examination is very complicated and misleading. For example, increasing IGF-1 inhibits GH secretion, increasing sugar has the same effect. 1- What is certain is that the stimulators of GH release in the body include galanin and insulin hypoglycemia, which act through beta-adrenergic blockers and have a stimulating effect on GH enhancement. 2- It is interesting to know that some alpha-2-adrenergic blockers such as yohimbine reduce the natural secretion of GH. 3- Some acetylcholinesterase inhibitors also facilitate the release of GH, which is caused by inhibiting the release of somatostatin.

4- Sleep, exercise, arginine and glucagon increase the secretion of GH, but atropine is one of the most effective GH blockers. 5- Androgenic substances in immature boys cause the release of GH. Estrogen also increases the concentration of GH, but it reduces the biological effect of the hormone by interrupting the production of IGF-1. 6- ACTH and TSH deficiency also causes GH deficiency (1).

Growth hormone, apart from its important effects on the growth of long bones, is the main and final regulator of height. It also controls the growth of pure tissues such as muscles and tendons and affects the metabolism of triple substances (sugars, fats and proteins). In this way, the composition of the body leads to an increase in net weight (LBM) [3]. The most important metabolic activity of GH is stimulating the process of protein synthesis (1, 4, 7). This hormone, by affecting the ribosomal stages of protein synthesis and also through the production of RNA (in the long term), increases the production of proteins in the target cells.This hormone increases the amount of protein production in the target cells by affecting the ribosomal stages of protein synthesis and also through the production of RNA (in the long term). Although no test has been conducted that directly compared anabolic steroids and growth hormone, the size of the effect of growth hormone on protein synthesis is several times the effect of anabolic steroids (4 and 12). The first studies that investigated the responses of growth hormone to exercise were done in 1963 by "Roth" [4] (12). Later extensive studies, especially in the study of "Shephard and Sidney" [5] in the mid-eighties, showed that exercise and physical activity are a strong stimulus for the secretion of growth hormone. Following their review, they stated that serum growth hormone levels increase during exercise, and this increase begins earlier with more intense activities. Considering the strong action of GH in the uptake of amino acids by muscle cells, it was concluded that growth hormone can improve sports performance by increasing muscle size and efficiency. Those who are unable to produce growth hormone have reduced muscle mass and are unable to exercise with normal efficiency and achieve normal athletic performance. When GH is given to these people even in small amounts, both their muscle mass returns to normal and their muscle efficiency returns to the original state during exercise. GH does this by directly stimulating muscle growth (4, 8, 10, 12). Supplemental GH and an active training program are expected to increase exercise performance more than exercise alone. Meanwhile, resistance exercises have a significant effect on GH response and the changes caused by such exercises depend on the following factors

amount of training load

volume of training or the total work done

number of training sets

rest period between sets

muscle mass used

level of physical fitness

stimulation threshold for GH secretion depends on a specific combination of these factors mentioned above. On the other hand, research shows that the secretion of growth hormone decreases with increasing age and also with increasing fat mass. In this way, it seems to be important to find exercises that can achieve these health and wellness factors in order to maintain proper body composition and physical efficiency. Despite the results of previous studies that people who have exercised compared to those who have not exercised will have more GH secretion, however, the response of growth hormone to exercise has not been confirmed (7,8,13,15). Limited research also shows that resting GH levels are not affected by exercise and physical activity, and there is some evidence that untrained individuals have lower blood GH levels during exercise. For this reason, most researchers suggest that the research in this field be continued until the answers to the ambiguities are found. For this purpose, in this research, it was tried to investigate the effect of resistance training on GH response in men aged 25 to 35, who have completed the puberty process. 1-3 Necessity and importance of research The concentration of growth hormone in the pituitary tissue is 5-15 mg/g, which means it is higher than the concentration of other pituitary hormones. The molecular weight of this hormone is 22,000 daltons. Like most of the pituitary hormones, growth hormone secretion does not have a continuous and uniform flow, but it is done in the form of pulsating flows [6]. The amount of secretion of this hormone is influenced by nervous stimulation and sleep and wakefulness. So that the plasma concentration of this hormone may increase 10 times within a few minutes. The greatest increase of the hormone in the plasma occurs shortly after falling asleep.

The effective factors in the secretion of growth hormone include

shock and nervous tension, pain, cold, surgery, hunger, hypoglycemia, exercise, eating protein foods and finally the amino acid arginine. Nervous shocks cause an increase in hormone secretion through the effect of cotacolamines on the hypothalamus. The effects of all the mentioned factors are justified due to the very important physiological property of growth hormone, which always prevents the consumption of glucose in the body.