EFFECTS OF PREPUBERTAL STRESS ON SUBSEQUENT ACTH RESPONSE TO NOVEL STRESS AND CRH IN MALE VS FEMALE RATS

Abstract

The effects of long-term chronic stress during prepubertal periods of growth and development on an organism's ability to release ACTH during future episodes of an acute novel stress and in response to exogenous CRH were examined. Following a 6-week stress period, in which prepubertal male and female WKY rats were subjected to three different and randomly given stress paradigms (heat, noise and immobilization) at various times of the day (in order to prevent adaptation to stress), chronically stressed male rats were far less able to respond to CRH plus a novel ether stress than were their male controls or their female counterparts. Although baseline ACTH levels were similar in both male and female control and experimental rats, when subjected to a subsequent acute ether stress, the differences in ACTH response between controls and experimentals as well as between males and females were significant. ACTH response to stressors was significantly blunted in both male and female experimental rats compared to their controls, but the male response was significantly lower than that of the females. These results suggest that prepubertal chronic stress may permanently alter an organism's ability to release ACTH, even when subjected to a novel and traumatic ether stress, and that males may be much more susceptible than females to prepubertal stress. Long-term stress, therefore, if experienced during critical developmental periods such as preadolescence, can permanently damage the stress response mechanism and cause other, more serious physiological disorders.