The acute effect of resistance exercise on serum growth hormone and blood glucose in healthy non-obese adolescent subject (original) (raw)
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The Journal of Clinical Endocrinology & Metabolism, 2006
Context: Recombinant human-GH (r-hGH), in supraphysiological doses, is self-administered by athletes in the belief that it is performance enhancing. Objective: The objective of this study was to determine whether r-hGH alters whole-body glucose and glycerol metabolism in endurance-trained athletes at rest and during and after exercise. Design: This was a 4-wk double-blind placebo-controlled trial. Setting: This study was conducted at St. Thomas Hospital (London, UK). Participants: Twelve endurance-trained male athletes were recruited and randomized to r-hGH (0.2 U/kg·d) (n = 6) or identical placebo (n = 6) for 4 wk. One (placebo group) withdrew after randomization. Intervention: Intervention was conducted by randomization to r-hGH (0.2 U/kg·d) or identical placebo for 4 wk. Main Outcome Measures: Whole-body rates of appearance (Ra) of glucose and glycerol (an index of lipolysis) and rate of disappearance of glucose were measured using infusions of d-[6–6-2H2]glucose and 2H5-glycerol...
The level of physical activity and the growth hormone (GH) response to acute physical exercise
Bosnian journal of basic medical sciences / Udruženje basičnih mediciniskih znanosti = Association of Basic Medical Sciences, 2004
There is no clear evidence about the influence of programmed physical activity (training) on growth hormone (GH) response to acute physical exercise. The aim of this study was to estimate the relationship between the level of physical activity and the serum growth hormone concentration in response to acute physical exercise. The study was performed on 20, healthy male subjects. Based on the level of their physical activities they were divided in two groups of equal size: group 1, trained, and group 2, untrained subjects. All subjects performed one boot of exercise on cycle ergometer, lasting 30 minutes. Work intensity was approx. 65% of VO2 max, and the rate of cycling was 60/min. Serum GH concentrations were measured by IRMA (immunoradiometric assays) method in blood samples obtained in the period of rest, during exercise and in the recovery period. There were marked differences in the dynamics of changes in the serum GH concentrations during exercise period between the groups of v...
Effects of Continuous Versus Intermittent Exercise, Obesity, and Gender on Growth Hormone Secretion
2010
Catecholamine release, growth hormone secretion, and energy expenditure during exercise vs. recovery in men. J Appl Physiol 89: 937-946, 2000.-We examined the relationship between energy expenditure (in kcal) and epinephrine (Epi), norepinephrine (NE), and growth hormone (GH) release. Ten men [age, 26 yr; height, 178 cm; weight, 81 kg; O 2 uptake at lactate threshold (LT), 36.3 ml ⅐ kg Ϫ1 ⅐ min Ϫ1 ; peak O 2 uptake, 49.5 ml ⅐ kg Ϫ1 ⅐ min Ϫ1 ] were tested on six randomly ordered occasions [control, 5 exercise: at 25 and 75% of the difference between LT and rest (0.25LT, 0.75LT), at LT, and at 25 and 75% of the difference between LT and peak (1.25LT, 1.75LT) (0900-0930)]. From 0700 to 1300, blood was sampled and assayed for GH, Epi, and NE. Carbohydrate (CHO) expenditure during exercise and fat expenditure during recovery rose proportionately to increasing exercise intensity (P ϭ 0.002). Fat expenditure during exercise and CHO expenditure during recovery were not affected by exercise intensity. The relationship between exercise intensity and CHO expenditure during exercise could not be explained by either Epi (P ϭ 1.00) or NE (P ϭ 0.922), whereas fat expenditure during recovery increased with Epi and GH independently of exercise intensity (P ϭ 0.028). When Epi and GH were regressed against fat expenditure during recovery, only GH remained statistically significant (P Ͻ 0.05). We conclude that a positive relationship exists between exercise intensity and both CHO expenditure during exercise and fat expenditure during recovery and that the increase in fat expenditure during recovery with higher exercise intensities is related to GH release. epinephrine; norepinephrine; metabolism THE "CROSSOVER CONCEPT" ASSERTS that, during incremental exercise, as exercise intensity is increased, a shift in substrate utilization occurs, with an increase in carbohydrate (CHO) metabolism and a decrease in fat metabolism . This notion could be explicable
The Response of Molecular Isoforms of Growth Hormone to Acute Exercise in Trained Adult Males
Journal of Clinical Endocrinology & Metabolism, 2001
Circulating GH consists of multiple molecular isoforms, all derived from the one gene in nonpregnant humans. To assess the effect of a potent stimulus to pituitary secretion on GH isoforms, we studied 17 aerobically trained males (age, 26.9 Ϯ 1.5 yr) in a randomized, repeat measures study of rest vs. exercise. Exercise consisted of continuous cycle ergometry at approximately 80% of predetermined maximal oxygen uptake for 20 min. Serum was assayed for total, pituitary, 22-kDa, recombinant, non-22-kDa, 20-kDa, and immunofunctional GH. All isoforms increased during, peaked at the end, and declined after exercise. At peak exercise, 22-kDa GH was the predominant isoform. After exercise, the ratios of non-22 kDa/total GH and 20-kDa GH/total GH increased and those of recombinant/pituitary GH decreased. The disappearance half-times for pituitary GH and 20-kDa GH were significantly longer than those for all other isoforms. We conclude that 1) all molecular isoforms of GH measured increased with and peaked at the end of acute exercise, with 22-kDa GH constituting the major isoform in serum during exercise; and 2) the proportion of non-22-kDa isoforms increased after exercise due in part to slower disappearance rates of 20-kDa and perhaps other non-22-kDa GH isoforms. It remains to be determined whether the various biological actions of different GH isoforms impact on postexercise homeostasis.
2000
The impact of sex and exercise duration on growth hormone secretion. Previous research clearly indicates a linear relationship between exercise intensity and growth hormone (GH) release and that this relationship is influenced by sex. The present study examined the GH response to increasing exercise duration in young men and women. Fifteen healthy subjects (8 men and 7 women) completed three randomly assigned exercise sessions (30, 60, and 120 min) at 70% of peak oxygen consumption. Blood samples were collected every 10 min beginning 30 min before exercise, for a total of 240 min. Total integrated GH concentration (IGHC) increased with increasing exercise duration for men and women (601, 1,394, and 2,360 g/l ⅐ 4 h; 659, 1,009 and 1,243 g/l ⅐ 4 h for 30, 60, and 120 min of exercise, respectively). Regression analysis revealed that IGHC (logarithmically transformed) was significantly influenced by exercise duration (logarithmically transformed) (120 min Ͼ 60 min Ͼ 30 min) and that a significant sex-dependent effect was present even after adjustments for fitness level and percent body fat (men Ͼ women). The slope of the regression line was greater for men than for women (1.003 vs. 0.612; P ϭ 0.013), but the average height of the regression line was greater for women (7.287 vs. 6.595; P Ͻ 0.001). Although GH secretory pulse half-duration was greater in women (P ϭ 0.001), and GH half-life was greater in men (P ϭ 0.001), they were not affected by exercise duration. The total mass of GH secreted during exercise increased with exercise duration (P Ͻ 0.001) but was not affected by sex (P ϭ 0.137). Results from the present investigation indicate that when exercise intensity is constant, exercise duration significantly increases IGHC and that this relationship is sex dependent. maximal oxygen consumption; endocrine Address for reprint requests and other correspondence: L. Wideman, Rm. 235. HHP Bldg.,
No influence of body composition on serum growth hormone response to acute dynamic exercise
Bosnian journal of basic medical sciences / Udruženje basičnih mediciniskih znanosti = Association of Basic Medical Sciences, 2006
Physical effort is a strong physiological stimulus that provokes an increase in blood growth hormone (GH) concentration. Interactions between GH and body composition are very complex. Seven athletes and seven age-matched controls completed a single 30-min bout of upright cycling exercise (5 % of VO(2max).) in order to estimate the influence of body composition on serum GH concentration during exercise. The serum GH concentration was measured in blood samples by standard immunoradiometric (IRMA) method. Anthropometric measurements were used for the calculation of body composition. There were no significant differences in total body mass or body mass index between the groups. The athletes had significantly less fat and higher bone and muscle mass. Serum GH concentration was 2.39 times higher in the athlets versus the control in the period of rest. During acute exercise, the serum GH concentration increased in both groups. No statistically significant differences between the groups in ...
Pilot study: an acute bout of high intensity interval exercise increases 12.5 h GH secretion
Physiological reports, 2018
The purpose of this study was to test the hypothesis that high-intensity interval exercise (HIE) significantly increases growth hormone (GH) secretion to a greater extent than moderate-intensity continuous exercise (MOD) in young women. Five young, sedentary women (mean ± SD; age: 22.6±1.3 years; BMI: 27.4±3.1 kg/m ) were tested during the early follicular phase of their menstrual cycle on three occasions. For each visit, participants reported to the laboratory at 1700 h, exercised from 1730-1800 h, and remained in the laboratory until 0700 h the following morning. The exercise component consisted of either 30-min of moderate-intensity continuous cycling at 50% of measured peak power (MOD), four 30-s "all-out" sprints with 4.5 min of active recovery (HIE), or a time-matched sedentary control using a randomized, cross-over design. The overnight GH secretory profile of each trial was determined from 10-min sampling of venous blood from 1730-0600 h, using deconvolution analys...
Clinical Endocrinology, 2005
Objectives Exercise is a potent physiological stimulus of GH secretion. We hypothesized that exogenous recombinant human growth hormone (rhGH) administration through an increase in GH and IGF-I levels would blunt the GH response to exercise. The aim of the study was to examine and compare the impact of rhGH on the exercise-induced GH response in healthy normal men and women. Design and Measurements Sixty-nine subjects (36 men, 33 women) were randomized to receive low-dose rhGH (0·1 U / kg / day), high dose rhGH (0·2 U / kg /day), or placebo. Subjects were matched for age (24 ± 3·1), and body mass index (BMI). rhGH was given as a single subcutaneous (s.c.) injection for the first 28 days. All subjects exercised to exhaustion (maximal oxygen consumption -VO 2 max) before rhGH treatment (Test 1), and on day 28 (Test 2). GH was measured before exercise (time 0), immediately after exercise (time 0′) and at 15, 30, 60, 90 and 120 min postexercise. Baseline IGF-I levels were measured before exercise on days 0 and 28. Results Baseline IGF-I levels showed no gender differences (42·3 women vs. 38·8 nmol / l men) but basal GH values were higher in women (9·9 vs. 1·8 mU / l, P < 0·001). The areas under the GH response curve, for Test 1 were similar in men and women. Peak GH values were higher in women than men (37·9 vs. 23·5 mU / l, but this did not quite reach statistical significance (P = 0·055). In men, administration of rhGH resulted in a significant increase in IGF-I levels over the basal state in both the LD and HD groups (P < 0·0001). In women, the increase in lGF-I levels reached significance only in the HD group (P < 0·0001). On day 28, GH secretion in response to exercise was calculated from the areas under the GH response curve correcting for an exogenous rhGH component (∆AUC). In men, the ∆AUC, for Test 2 were similar in all three groups. In women, the ∆AUC was higher in the placebo group, than in the HD group (P < 0·02). Free T4 levels decreased significantly in men, and free T3 increased in both men and women, in HD group after the rhGH administration. TSH levels were suppressed only in women. No changes in sex hormones were found in men or women in any of the treatment groups. Conclusions In terms of IGF-I, men are more responsive to rhGH treatment than women. In addition, as men, but not women, were able to overcome the negative feedback control of the elevated IGF-I levels, it seems that exercise may be a more robust stimulus to GH release in men compared to women.
Human growth hormone response to repeated bouts of aerobic exercise
Journal of Applied Physiology, 1997
Kanaley, J. A., J. Y. Weltman, J. D. Veldhuis, A. D. Rogol, M. L. Hartman, and A. Weltman. Human growth hormone response to repeated bouts of aerobic exercise. J. Appl. Physiol. 83(5): 1756–1761, 1997.—We examined whether repeated bouts of exercise could override growth hormone (GH) auto-negative feedback. Seven moderately trained men were studied on three occasions: a control day (C), a sequential exercise day (SEB; at 1000, 1130, and 1300), and a delayed exercise day (DEB; at 1000, 1400, and 1800). The duration of each exercise bout was 30 min at 70% maximal O2 consumption (V˙o 2 max) on a cycle ergometer. Standard meals were provided at 0600 and 2200. GH was measured every 5–10 min for 24 h (0800–0800). Daytime (0800–2200) integrated GH concentrations were ∼150–160% greater during SEB and DEB than during C: 1,282 ± 345, 3,192 ± 669, and 3,389 ± 991 min ⋅ μg ⋅ l−1for C, SEB, and DEB, respectively [SEB > C ( P < 0.06), DEB > C ( P < 0.03)]. There were no differences in ...