Prolonged treatment with gamma-aminobutyric acid (GABA)-mimetic substances in prepubertal male rats.

The effect of chronic treatment with a gamma-aminobutyric acid (GABA)-mimetic compound, progabide, and an inhibitor of GABA-transaminase, gamma-acetylenic GABA (GAG), was tested in prepubertal male rats. The effect of gamma-butyrolactone (GBL), given orally, was also tested. The rats treated with progabide did not show any difference in body, testicular, or seminal vesicle weights or serum prolactin levels, as compared with control rats. Treatment with GAG, at both dose levels used, did not significantly affect body weight. Testicular weight was significantly lower in the group of rats treated with the low dosage of GAG (5 mg/kg), and serum prolactin was significantly lower in the rats treated with the high dosage of GAG (20 mg/kg) as compared with control rats. In the first experiment performed with GBL, the rats given this compound had significantly lower body and testicular weights as compared with control rats. In the second experiment, GBL-treated rats had body weights similar to those of control rats, but testicular weights were significantly decreased. Prolonged treatment with GABA mimetics may affect the hypothalamic-pituitary-testicular axis.