THE HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL SYSTEM AND SLEEP IN MAN

This review article summarizes the major findings about the interactio ns of human sleep structure and the hypothalamo-pituitary-adrenocortic al (HPA) system under physiological and pathophysiological conditions, including studies that probe the sleep effects of systemically admini stered HPA hormones. Human sleep is regulated by a concerted action of various signal compounds acting at sleep-generating neurons whose cen tral organization is not yet fully understood. During nocturnal sleep the endocrine system is remarkably active, the longest established fin ding being that growth hormone (GH) release is associated with the ini tiation of sleep and that there is a steep morning rise of cortisol (W eitzman er al., 1966; Takahashi et al., 1968). Moreover, the effects o f exogenously administered corticosteroids and of their excessive endo genous release (e.g. Gushing's disease) were recognized more than 20 y ears ago.