Corticotropin releasing hormone is involved in exercise-induced elevation in core temperature

Abstract

To determine the involvement of corticotropin releasing factor (CRF) in exercise-induced elevation in core temperature of female rats, CRF antibody or vehicle was injected intracerebroventricularly (ICV) into rats that had free access to exercise wheels for 6 weeks. On the day of injection, there were no differences in body temperature or activity following these injections. However, exercising animals had a significantly attenuated daytime temperature when compared to vehicle control animals at one day postinjection with the CRF antibody. Although these animals have significantly lower body temperature than the animals that received vehicle, the injection of CRF antibody had no effect on locomotor activity. Therefore, this decrease in temperature is not due to a reduction in activity. These results suggest that CRF is involved in the exercise-induced elevation in daytime body temperature. Since the antibody also attenuates fevers caused by IL-1[beta] (and presumably other cytokines), it is possible that the daytime elevation in body temperature of exercising rats is mediated by IL-1[beta] other cytokines.