Male aging and hormones: the adrenal cortex.

The hypothalamic-pituitary-adrenal (HPA) axis in the aging male (adrenopause) is characterized by an unexplained reduction of DHEA secretion while ACTH and cortisol show no major changes, except for a lower amplitude of 24-h fluctuations and a tendency to higher cortisol values in the evening and night (especially in dementia). As a consequence, the cortisol/DHEAS ratio tends to be higher. Adrenocortical morphology reveals an age-related reduction in the thickness of the zona reticularis, and an increase of microhemorrhagic events. This may be one of the underlying causes of the age-dependent high frequency of adrenal nodules incidentally found in the elderly, which may seldom be hormonally active.