Response of the Hypothalamic-Pituitary-Adrenal Axis to Stress in the Absence and Presence of Ethanol in Subjects at High and Low Risk of Alcoholism

Abstract

Both genetic and environmental factors, such as stress, are important in determining alcohol consumption. Furthermore, both stress and alcohol influence the activity of the hypothalamic-pituitary-adrenal (HPA)-axis. Thus, the present studies investigated the response of the HPA axis to stress and the effect of ethanol on the stress response, in subjects at high (HR) and low (LR) risk of alcoholism as determined from their family history. Twenty HR and 20 LR subjects performed a stress-inducing task 30 min following the ingestion of either a placebo drink or a low dose of ethanol. The levels of plasma adrenal corticotropic hormone (ACTH) and cortisol were measured prior to and for four hours following initiation of the treatment. Changes with time in the plasma hormone levels following ingestion of either a placebo or an ethanol drink, without the performance of the stress task, served as controls to compare the stress-induced changes. Neither the placebo nor the ethanol drink altered the plasma ACTH and cortisol concentrations. High risk subjects presented lower basal ACTH, but not cortisol, levels and a lower stress-induced increase in plasma ACTH concentration than LR subjects. Furthermore, the HR subjects presented a delayed post-stress recovery of the plasma ACTH and cortisol levels. Ethanol consumption prior to the stress task attenuated (ACTH) or abolished (cortisol) the stress-induced increase in the plasma hormone concentrations of both LR and HR subjects. Thus, there are quantitative differences on the response of the HPA-axis to stress between HR and LR subjects, while ingestion of low amounts of ethanol prior to the performance of the stress task had a similar effect on HR and LR individuals.