Age dependence of plasma oestrogen response to HCG and ACTH in men.

Twelve men, 19-40 years old, and 12 men, 60-86 years old, were given ACTH and in a second test series, HCG. Oestrone, oestradiol-17beta and cortisol were measured in the plasma before and after stimulation. Under basal conditions oestrone and oestradiol as well as the percentage binding of testosterone increased significantly with age, whereas cortisol remained unchanged. The administration of HCG resulted in higher levels of both plasma oestrone and oestradiol in older subjects than in younger ones, although the percentage increase was smaller. ACTH stimulation leads to higher levels of oestrone in the older group, whereas oestradiol remained unchanged. Cortisol rose 3.5 fold in both groups. Regarding absolute concentrations of oestrone and oestradiol the ability of the adrenals and of the testes to respond to exogenous gonadotrophin and adrenocorticotrophin appeared to be preserved despite ageing, though the relative responses of oestrone and oestradiol after HCG and of oestrone after ACTH were decreased in old as compared to young men.