The effect of in vitro ethanol exposure on LHRH release from perifused rat hypothalami.

A variety of indirect data suggest that the luteinizing hormone (LH) lowering effects of ethanol (ETOH) are mediated at a hypothalamic level decreasing the synthesis and/or release of LH-releasing hormone (LHRH). Little direct data support this concept, however. The current study was, therefore, designed utilizing a perifusion system with frequent sampling for LHRH with and without ethanol added to determine if ethanol had a direct effect on basal or stimulated LHRH release. A variety of secretagogues, including dopamine, norepinephrine, naloxone, prostaglandin E2, and a high dose of potassium were utilized. Ethanol at a dose of 300 mg% did not alter either basal or secretagogue-stimulated LHRH release from the hypothalami of ethanol-naive male rats. Thus, ethanol did not appear to have a direct effect on LHRH in this system. Alterations in LHRH release by ethanol may occur at a suprahypothalamic level, involving neurotransmitter-LHRH interactions. Alternatively, the well-described lowering effect of ethanol on LH may be secondary to a direct pituitary locus of action, or involve a metabolic breakdown product of ethanol rather than ethanol itself.