TY - JOUR

T1 - Growth Hormone Receptor Antagonist Treatment Reduces Exercise Performance in Young Males

AU - Goto, K.

AU - Doessing, S.

AU - Nielsen, R.H.

AU - Flyvbjerg, A.

AU - Kjaer, M.

N1 - Times Cited: 0ArticleEnglishGoto, KWaseda Univ, Fac Sport Sci, 2-579-15 Mikajima, Tokorozawa, Saitama 3591192, JapanCited References Count: 37491NBENDOCRINE SOC8401 CONNECTICUT AVE, SUITE 900, CHEVY CHASE, MD 20815-5817 USACHEVY CHASE

PY - 2009

Y1 - 2009

N2 - Context: The effects of GH on exercise performance remain unclear. Objective: The aim of the study was to examine the effects of GH receptor (GHR) antagonist treatment on exercise performance. Design: Subjects were treated with the GHR antagonist pegvisomant or placebo for 16 d. After the treatment period, they exercised to determine exercise performance and hormonal and metabolic responses. Participants: Twenty healthy males participated in the study. Intervention: Subjects were treated with the GHR antagonist (n = 10; 10 mg/d) or placebo (n = 10). After the treatment period, they performed a maximal oxygen uptake ((V) over dotO(2max)) test and a prolonged exercise test, consisting of 60 min of submaximal cycling followed by exercise to fatigue at 90% of (V) over dotO(2max). Main Outcome Measures: (V) over dotO(2max) was measured before and after the treatment period. Hormonal and metabolic responses and time to exhaustion during prolonged exercise were determined. Results: Resting serum IGF-I concentration decreased by 20% in the GHR antagonist-treated group (P < 0.05), whereas no change was observed in the placebo group. Conversely, resting serum GH concentration was significantly higher in the treatment group compared with the placebo group (P < 0.01). (V) over dotO(2max) did not change significantly in either group after the treatment period. Time to exhaustion at 90% of (V) over dotO(2max) was significantly shorter in the treatment group (P < 0.05). No significant differences were observed between the groups in terms of changes in serum free fatty acids, glycerol, (V) over dotO(2), or relative fat oxidation. Conclusion: GH might be an important determinant of exercise capacity during prolonged exercise, but GHR antagonist did not alter fat metabolism during exercise. (J Clin Endocrinol Metab 94: 3265-3272, 2009) Udgivelsesdato: 2009/9

AB - Context: The effects of GH on exercise performance remain unclear. Objective: The aim of the study was to examine the effects of GH receptor (GHR) antagonist treatment on exercise performance. Design: Subjects were treated with the GHR antagonist pegvisomant or placebo for 16 d. After the treatment period, they exercised to determine exercise performance and hormonal and metabolic responses. Participants: Twenty healthy males participated in the study. Intervention: Subjects were treated with the GHR antagonist (n = 10; 10 mg/d) or placebo (n = 10). After the treatment period, they performed a maximal oxygen uptake ((V) over dotO(2max)) test and a prolonged exercise test, consisting of 60 min of submaximal cycling followed by exercise to fatigue at 90% of (V) over dotO(2max). Main Outcome Measures: (V) over dotO(2max) was measured before and after the treatment period. Hormonal and metabolic responses and time to exhaustion during prolonged exercise were determined. Results: Resting serum IGF-I concentration decreased by 20% in the GHR antagonist-treated group (P < 0.05), whereas no change was observed in the placebo group. Conversely, resting serum GH concentration was significantly higher in the treatment group compared with the placebo group (P < 0.01). (V) over dotO(2max) did not change significantly in either group after the treatment period. Time to exhaustion at 90% of (V) over dotO(2max) was significantly shorter in the treatment group (P < 0.05). No significant differences were observed between the groups in terms of changes in serum free fatty acids, glycerol, (V) over dotO(2), or relative fat oxidation. Conclusion: GH might be an important determinant of exercise capacity during prolonged exercise, but GHR antagonist did not alter fat metabolism during exercise. (J Clin Endocrinol Metab 94: 3265-3272, 2009) Udgivelsesdato: 2009/9

M3 - Journal article

VL - 94

SP - 3265

EP - 3272

JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

SN - 0021-972X

IS - 9

ER -