Assessment of the role of the glucocorticoid system in aging processes and in the action of food restriction.

The Glucocorticoid Cascade Hypothesis of Aging and the hypothesis that food restriction retards the aging processes by preventing the development with age of hyperadrenocorticism were investigated. A longitudinal life span study of the daily concentration pattern of plasma corticosterone was conducted in male Fischer 344 rats fed ad libitum or restricted to 60% of the mean food intake of ad libitum fed rats. In another group of ad libitum fed and food-restricted rats, the influence of age on the response of plasma corticosterone levels to restraint stress was measured as was the time course of the return of plasma corticosterone to basal levels following the stress. The findings do not support the hypothesis that food restriction retards the aging processes by preventing the development of hyperadrenocorticism with advancing age. They also indicate that the Glucocorticoid Cascade Hypothesis does not describe a major aspect of the aging processes. Rather, the results suggest the possibility that a lifetime of daily periods of mild hyperadrenocorticism may, if anything, retard the aging processes.