NALOXONE TREATMENT ALTERS THE INHIBITORY EFFECT OF GAMMA-HYDROXYBUTYRIC ACID ON LUTEINIZING-HORMONE SECRETION IN MALE-RATS

The effects of intraperitoneal administration of gamma-hydroxybutyric acid (GHB) on luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in male rats were studied. A significant decrease in plasma LH levels was observed one hour after GHB administration (100 mg/kg), while plasma FSH levels was not altered. The pretreatment with GABAergic antagonists (picrotoxin and bicuculline) did not affect the inhibitory action of GHB on LH levels. However, pretreatment with naloxone, a opiate blocking agent, suppressed the inhibitory action of GHB on LH secretion. The results suggest that GHB exercts an inhibitory effect on LH secretion and supports previous findings that the actions of GHB are mediated by the endogenous opiate system.