AGE-ASSOCIATED CHANGES OF PITUITARY-ADRENOCORTICAL HORMONE REGULATIONIN HUMANS - IMPORTANCE OF GENDER

In the present study the hypothesis was tested that in normal human ag ing an insensitivity of the glucocorticoid feedback signal is acquired . Thus, 40 healthy elderly (mean age: 69 +/- 5 years) and 20 younger ( mean age: 34 +/- 8 years) individuals underwent a combined dexamethaso ne suppression/CRH-stimulation test. Cortisol secretion after dexameth asone (DEX) pretreatment and before CRH was increased in the older age group, but none of the subjects escaped DEX-induced suppression of co rtisol. However, after additional CRH administration to the DEX-pretre ated volunteers, the older group released significantly more cortisol than their young counterparts. Within the group of the elderly only, a positive correlation between BASAL, DEX-pretreated cortisol concentra tion and post-CRH steroid responses was found. Gender profoundly affec ted DEX/CRH-test outcome: females, regardless of age, had an increased hormonal secretion in comparison to males. It is concluded that, duri ng human aging, adaptive changes in glucocorticoid receptors take plac e, allowing for the system to maintain ''peripheral'' glucocorticoid h omeostasis, but that more sophisticated challenge procedures such as t he DEX/CRH test reveal an age-related increase in HPA system activity.