In-vivo effect of ethanol on release of LH-releasing hormone and LH in rats.

The effect of exposure to ethanol on hypothalamic LH-releasing hormone (LHRH) release in vivo was investigated in rats both acutely (i.p. injection) and after 3 days of administration, utilizing a permanent gastric cannula. In both designs, the animals were castrated before being given ethanol and, in both experiments, ethanol successfully lowered the post-castration LH rise compared with control castrated animals. In both the acutely and chronically treated groups, basal LHRH release was not impaired, despite the documented decrease in LH levels. Finally, stimulated LHRH release was investigated with depolarizing concentrations of potassium and, again, no change was noted between the hypothalamic release of this decapeptide in the ethanol-exposed compared with the ethanol-naive animals. Thus, ethanol failed to inhibit basal or stimulated LHRH secretion in the acutely and chronically treated animal. This lack of effect on LHRH occurred despite a concomitant lowering of serum concentrations of LH.