Oral L-arginine before resistance exercise blunts growth hormone in strength trained males.
Int J Sport Nutr Exerc Metab
; 24(2): 236-44, 2014 Apr.
Article
en En
| MEDLINE
| ID: mdl-24225560
ABSTRACT
Acute resistance exercise and L-arginine have both been shown to independently elevate plasma growth hormone (GH) concentrations; however, their combined effect is controversial. The purpose was to investigate the combined effects of resistance exercise and L-arginine supplementation on plasma L-arginine, GH, GH secretagogues, and IGF-1 in strength trained participants. Fourteen strength trained males (age 25 ± 4 y; body mass 81.4 ± 9.0 kg; height 179.4 ± 6.9 cm; and training experience 6.3 ± 3.4 y) participated in a randomized double-blind crossover design (separated by ~7 days). Subjects reported to the laboratory at 0800 in a fasted state, consumed L-arginine (ARG; 0.075 g·kg-1 body mass) or a placebo (PLA) before performing an acute bout of resistance exercise (3 sets of 8 exercises, 10 repetitions at ~75% 1RM). Blood samples were collected at rest, before exercise, and at 0, 15, 30, and 60 min of rest-recovery. The ARG condition significantly increased plasma L-arginine concentrations (~120%) while no change was detected in the PLA condition. There were no differences between conditions for GH, GH-releasing hormone, ghrelin, or IGF-1 at any time point. GH-inhibiting hormone was significantly lower in the ARG condition. However, integrated area under the curve for GH was blunted in the ARG condition (L-arginine = 288.4 ± 368.7 vs. placebo = 487.9± 482.0 min·ng·mL1, p < .05). L-arginine ingested before resistance exercise significantly elevated plasma L-arginine concentration but attenuated plasma GH in strength trained individuals despite a lower GHIH. Furthermore our data shows that the GH suppression was not due to a GH or IGF-1 induced autonegative feedback loop.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Arginina
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Hormona de Crecimiento Humana
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Fuerza Muscular
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Entrenamiento de Fuerza
Tipo de estudio:
Clinical_trials
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Prognostic_studies
Límite:
Adult
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Humans
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Male
Idioma:
En
Revista:
Int J Sport Nutr Exerc Metab
Asunto de la revista:
CIENCIAS DA NUTRICAO
/
MEDICINA ESPORTIVA
/
METABOLISMO
Año:
2014
Tipo del documento:
Article
País de afiliación:
Canadá