MELATONIN AND CORTISOL CIRCADIAN SECRETION DURING ETHANOL WITHDRAWAL IN CHRONIC-ALCOHOLICS

Changes in central neurotransmission and in hypothalamo-pituitary func tion occur in both ethanol (ETOH) intake and withdrawal. Melatonin (ML T) secretion is regulated by the noradrenergic system, which is activa ted upon ETOH withdrawal. Experimental evidence exsist that pineal gla nd may have a role in ETOH intake and preference in rats. Twenty-four hour urinary excretion of MLT was found to be increased during ETOH in take in chronic alcoholics. In this study we have determined 24h plasm a levels of MLT and cortisol in 8 chronic alcoholic males hospitalized for a detoxication program and in 8 healthy controls. The study was p erformed just after admission, on the first day of ETOH withdrawal and after 14 days of controlled abstinence. Circadian periodicity has bee n evaluated by the cosinor method. The initial determinations correspo nded to the acute withdrawal phase. Twenty-four hour plasma MLT mean l evels on acute withdrawal were higher than after 14 days abstinence an d than those found in controls. Large interindividual differences prev ented the detection of statistical significance. The cosinor analysis disclosed the loss of circadian periodicity in the acute withdrawal. S ignificant 24h periodicity was restored after 14 days abstinence. Cort isol levels were significantly higher than those found on day 14 and i n healthy controls. Twenty-four hour periodicity was maintained in bot h alcoholics series. A delay in cortisol acrophase occurred in acute w ithdrawal. The effects of Corticotropin Releasing Hormone infusion on cortisol secretion were significantly enhanced in the acute withdrawal phase in comparison with those occurring when patients were retested and with healthy controls.