Central corticotropin releasing factor reduces natural cytotoxicity. Time course of action

Corticotropin-releasing factor (CRF) administered intracerebroventricularly produced both a rapid, greater than 50% reduction in splenic natural killer (NK) cytotoxicity and a prolonged elevation in plasma corticosterone levels. In the first 60 minutes following CRF, fivefold increases in corticosterone levels were associated with the suppression of NK activity. However, NK activity returned to control levels at later time points even though elevated plasma corticosterone levels persisted. These data augment the findings that central CRF reduces natural cytotoxicity and establish a time course for the effect in acutely treated rats.