Plasma and urinary 17-hydroxycorticosteroid responses to 72-hr. avoidance sessions in the monkey.

Abstract

Marked elevations in both mean urinary and mean 9 A.M. plasma 17-OHCS levels are associated with 72-hr. avoidance sessions in the monkey. The urinary 17-OHCS elevations persist also for several days in the recovery period. The 17-OHCS elevations, while substantial, do not appear to represent maximal adrenal cortical responses and no evidence of adrenal cortical exhaustion was observed. Indirect evidence suggests rather the hypothesis that neural suppressive or governing mechanisms may come into play as avoidance is sustained. Repetition of the 72-hr. avoidance experience is generally associated with both diminishing basal urinary 17-OHCS levels and urinary 17-OHCS response to avoidance. After 6 sessions at monthly intervals, however, a substantial urinary 17-OHCS response was obtained when the intensity of the emotional stimulus was increased. Substantial individual differences were observed between monkeys with respect to mean urinary 17-OHCS response to avoidance. Highly significant correlations were observed between these individual differences in 17-OHCS response and similar individual differences in mean lever response rate before, during, and after avoidance. Evidence is presented that, following temporary initial disruption, diurnal changes in plasma and urinary 17-OHCS levels persist throughout the stressful period. It is concluded that the 17-OHCS responses indicate that the stressful conditions in these experiments are of sufficient severity to provide a suitable test for the possible responsivity of other endocrine systems to a stressful situation in which predominantly psychological factors are involved.