ACUTE EFFECT OF AMINO-ACID INGESTION AND RESISTANCE EXERCISE ON PLASMA GROWTH-HORMONE CONCENTRATION IN YOUNG MEN

Sixteen men completed four trials at random as follows: (Trial A) perf ormance of a single bout of resistance exercise preceded by placebo in gestion (vitamin C); (Trial B) ingestion of 1,500 mg L-arginine and 1, 500 mg L-lysine, immediately followed by exercise as in Trial A; (Tria l C) ingestion of amino acids as in Trial B and no exercise; (Trial D) placebo ingestion and no exercise. Growth hormone (GH) concentrations were higher at 30, 60, and 90 min during the exercise trials (A and B ) compared with the resting trials (C and D) (p<.05). No differences w ere noted in [GH] between the exercise trials. [GH] was significantly elevated during resting conditions 60 min after amino acid ingestion c ompared with the placebo trial. It was concluded that ingestion of 1,5 00 mg arginine and 1,500 mg lysine immediately before resistance exerc ise does not alter exercise-induced changes in [GH] in young men. Howe ver, when the same amino acid mixture is ingested under basal conditio ns, the acute secretion of GH is increased.