ENHANCED SENSITIVITY OF PITUITARY BETA-ENDORPHIN TO ETHANOL IN SUBJECTS AT HIGH-RISK OF ALCOHOLISM

Background: Previous studies have demonstrated that a moderate dose of ethanol induced a significant increase in the plasma beta-endorphin c ontent of subjects from families with a history of alcoholism (high ri sk [HR]), but not of subjects from families without a history of alcoh olism (low risk [LR]). The objective of this study was to examine the response of the pituitary beta-endorphin and adrenal cortisol systems to various concentrations of ethanol in male and female subjects at hi gh and low risk of the future development of alcoholism.Methods: All s ubjects participated in four experimental sessions. In each session th e subjects were given a drink containing one of the following doses of ethanol: 0, 0.25, 0.50, and 0.75 g of ethanol per kilogram of body we ight (for a 60- to 70-kg individual). Blood samples were taken at 0 mi nutes and at 15, 45, 120, and 180 minutes after the drink for estimati on of the blood alcohol, plasma beta-endorphin, and plasma cortisol le vels. Results: The concentration of alcohol in the blood at various in tervals after the drink was similar among the subjects, regardless of the risk group. Ethanol increased the plasma level of beta-endorphin-r elated peptides of the HR but not of the LR subjects in a dose-depende nt manner. All subjects showed a small decrease in plasma cortisol lev el with time, but ethanol ingestion did not significantly alter the pl asma cortisol levels. Conclusion: This study indicates that the pituit ary beta-endorphin system, but not the adrenal cortisol system, of the HR subjects shows an enhanced sensitivity to ethanol, which may be an important factor in controlling ethanol consumption.