| Gender governs the relationship between exercise intensity and growth hormone release in young adults. | |
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MedLine Citation:
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PMID: 11960957 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We previously reported that in young adult males growth hormone (GH) release is related to exercise intensity in a linear dose-response manner (Pritzlaff et al. J Appl Physiol 87: 498-504, 1999). To investigate the effects of gender and exercise intensity on GH release, eight women (24.3 +/- 1.3 yr, 171 +/- 3.2 cm height, 63.6 +/- 8.7 kg weight) were each tested on six randomly ordered occasions [1 control condition (C), 5 exercise conditions (Ex)]. Serum GH concentrations were measured in samples obtained at 10-min intervals between 0700 and 0900 (baseline) and 0900 and 1300 (Ex + recovery or C). Integrated GH concentrations (IGHC) were calculated by trapezoidal reconstruction. During Ex, subjects exercised for 30 min (0900-0930) at one of the following intensities [normalized to the lactate threshold (LT)]: 25 and 75% of the difference between LT and rest, at LT, and at 25 and 75% of the difference between LT and peak O2 uptake. No differences were observed among conditions for baseline IGHC. To determine whether total (Ex + recovery) IGHC changed with increasing exercise intensity, slopes associated with individual linear regression models were subjected to a Wilcoxon signed-rank test. To test for gender differences, data in women were compared with the previously published data in men. A Wilcoxon ranked-sums two-tailed test was used to analyze the slopes and intercepts from the regression models. Total IGHC increased linearly with increasing exercise intensity. The slope and intercept values for the relationship between total IGHC and exercise intensity were greater in women than in men. Deconvolution analysis (0700-1300 h) revealed that, regardless of gender, increasing exercise intensity resulted in a linear increase in the mass of GH secreted per pulse and summed GH production rate, with no changes in GH secretory pulse frequency or apparent half-life of elimination. Exercise reduced the half-duration of GH secretory burst in men but not in women. Gender comparisons revealed that women had greater basal (nonpulsatile) GH secretion across all conditions, more frequent GH secretory pulses, a greater GH secretory pulse amplitude, a greater production rate, and a trend for a greater mass of GH secreted per pulse than men. We conclude that, in young adults, the GH secretory response to exercise is related to exercise intensity in a linear dose-response pattern. For each incremental increase in exercise intensity, the fractional stimulation of GH secretion is greater in women than in men. |
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Authors:
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Cathy J Pritzlaff-Roy; Laurie Widemen; Judy Y Weltman; Rob Abbott; Margaret Gutgesell; Mark L Hartman; Johannes D Veldhuis; Arthur Weltman |
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Publication Detail:
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Type: Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 92 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2002 May |
Date Detail:
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Created Date: 2002-04-18 Completed Date: 2002-06-21 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 2053-60 Citation Subset: IM |
Affiliation:
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Department of Human Services, General Clinical Research Center, University of Virginia, Charlottesville 22903, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Body Composition / physiology Exercise Test Female Human Growth Hormone / blood* Humans Lactic Acid / blood Linear Models Oxygen Consumption / physiology Physical Exertion / physiology* Sex Factors Time Factors |
| Grant Support | |
ID/Acronym/Agency:
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RR-00847/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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12629-01-5/Human Growth Hormone; 50-21-5/Lactic Acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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