Regulation of amino acid activating enzymes of guinea pig tissues by androgens

Castration of adult male guinea pigs produced a gradual decrease in the specific activity of the amino acid activating enzymes (ATP-pyrophosphate 32 exchange) of the seminal vesicles to approximately 40% of the normal in about 40 days. The administration of testosterone, testosterone propionate, or androstan-17ß-ol, 3-one gradually restored the specific activity of the enzymes, but a higher dose of the androgen was needed than that required to restore the tissue weight. The enzyme activities of the prostate and temporal muscles were not altered by castration or androgen administration. The use of grouped or individual amino acids as substrate in the exchange reaction yielded the same pattern of responses as when a mixture of 17 amino acids was used as substrate.