AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 4 856-R863, Copyright © 1995 by American Physiological Society
Castration attenuates prolactin response but potentiates ACTH response to conditioned stress in the rat
E. W. Bingaman, L. D. Van de Kar, J. M. Yracheta, Q. Li and T. S. Gray
Department of Cell Biology, Loyola University of Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA.
The purpose of this study was to examine the effect of circulating
androgens on neuroendocrine, autonomic, and behavioral responses to stress.
The effects of conditioned stress were studied in male Sprague-Dawley rats
that were intact, gonadectomized, or gonadectomized and treated with
dihydrotestosterone (DHT). Intact animals received sham surgeries. Animals
were stressed 3 wk after surgery. The adrenocorticotropic hormone (ACTH)
response to conditioned stress was significantly potentiated (P < 0.01)
in gonadectomized males compared with sham-operated and gonadectomized
DHT-treated animals. In stressed rats, plasma corticosterone levels were
significantly higher (P < 0.05) in gonadectomized animals compared with
DHT-treated castrates. The prolactin response to stress was decreased (P
< 0.01) in gonadectomized males compared with sham-operated and
gonadectomized DHT-treated rats. The stress-induced increases in plasma
renin activity and concentration were not altered in gonadectomized or in
gonadectomized DHT-treated animals. Nonstressed DHT-treated castrates
exhibited more "fearlike" behavior compared with nonstressed sham-operated
and gonadectomized animals. However, conditioned stress produced the same
behavioral effects in all treatment groups. The results demonstrate that
the ACTH/corticosterone, prolactin, and behavioral responses to a
psychological stressor are differentially regulated by circulating
androgens.
