Cortisol and beta-endorphin response in alcoholics and alcohol abusers following a high naloxone dosage

The course of plasma cortisol and beta-endorphin-like immunoreactivity (beta-EP-IR) was determined following a single i.v. administration of 20 mg naloxone. The test subjects included 20 male alcoholics (medication-free), investigated one to three days and four weeks after the onset of abstinence, as well as 10 short-time abstinent alcohol abusers and 10 healthy control subjects. The mean baseline values of cortisol and beta-EP-IR remained within normal limits in all groups. The significant decrease in the plasma cortisol baseline values in the alcoholics after 4 weeks abstinence may indicate a lower level of the regulation of the hypothalamic-pituitary-adrenal axis (HPA) under conditions of abstinence. After naloxone administration an increase in plasma cortisol and beta-EP-IR was observed in all groups. The multivariate trend analysis showed significant differences in the time course of plasma cortisol between the three groups, however not in the course of beta-EP-IR. The changes in the dynamic regulation of the HPA axis, resulting from chronic alcohol consumption, appears to be irrespective of whether the drinking pattern is dependent or abusive. In alcoholics these changes could still be identified following a 4-week abstinence period.