Effect of acute corticotropin releasing factor on pituitary-adrenocortical responsiveness in elderly women and men

Aging is related to critical changes of the hypothalamo-pituitary-adrenal function. A decline in serum DHEA levels has been demonstrated in healthy elderly subjects, while ACTH and cortisol concentrations remain at normal values. The purpose of the present study was to investigate the effect of aging on pituitary-adrenal responsiveness to hCRF in subjects of both sexes. A group of 12 physically and mentally healthy elderly subjects and a group of 12 young controls of both sexes have been selected. Blood samples were collected before and after iv bolus injection of hCRF; ACTH, cortisol and DHEA levels were then determined by RIA. Basal ACTH and cortisol levels did not result statistically different between controls and elderly subjects, while DHEA showed a clear and significant age-related decrease (p < 0.01). Following the hCRF injection, the responses of ACTH, cortisol and DHEA in aged subjects were higher than in young controls; ACTH (p < 0.03) and cortisol (p < 0.01) were higher in aged women than in men. The present study demonstrated that aging is associated with an increased responsiveness of ACTH, cortisol and DHEA to exogenous hCRF supply. A hyperactivation of the pituitary-adrenal secretory activity may explain the age-related of the same axis. Gender probably has a significant influence on basal and stimulated hormonal secretion. In conclusion, hCRF test may become a useful clinical tool in establishing a neuroendocrine correlation with central disturbances associated to aging