On the gender differences in sleep-endocrine regulation in young normal humans

Sleep-endocrine regulation in humans involves high activity of the somatotr opic axis at the beginning of the night and an increase in the hypothalamic -pituitary-adrenocortical (HPA) system during the night. Gender differences were examined with regard to sleep-endocrine regulation in young healthy c ontrols (10 men, 9 women). The sleep EEG was recorded (23:00-07:00 h) and p lasma samples were collected and analyzed for GH, cortisol and ACTH at 20-m in intervals. Cortisol secretion was significantly higher in females during the first half of the night (F = 9.9, p < 0.05), while ACTH was not differ ent. In women, sleep-EEG analysis showed less slow wave sleep (SWS) during the second half of the night (F = 4.5, p < 0.05) and a significantly greate r decrease in SWS and delta activity from the first to the second half of t he night (F = 3.7 and 7.4, respectively, p < 0.05). Sigma activity increase d during the night in women only (F = 3.7, p < 0.05), Our data are compatib le with the hypothesis that in women compared to men activity of hypothalam ic CRH neurons and central CRH release is greater, but is not reflected by greater HPA activity.