Endocrine Abstracts

Under non-stressed conditions adrenal glucocorticoid (GC) secretion shows strong circadian rhythms with blood levels peaking around wake-up time (i.e. in the morning in humans and at the beginning of the night in nocturnal rodents). These diurnal variations are primarily regulated by rhythmic activation of the hypothalamic–pituitary–adrenal (HPA) axis and the secretion of ACTH from the pituitary. While circadian HPA axis activity is ultimately controlled by the circa...