Regulation of Heat Production in Gold-Adapted Rats. ∗

Summary

(1). The capacity of cold-adapted and non-adapted rats to increase heat production by non-shivering regulatory means was tested. In both groups, muscular activity was blocked by curare. Only cold-adapted animals could increase heat production sufficiently to maintain body temperature as the test room was cooled. Adrenodemedullation reduced somewhat the ability of the cold-adapted rats to increase heat production, but made little change in the response of non-adapted animals. It is suggested that this regulation results from the release of adrenal and extra-adrenal epinephrine and that the increased heat production by cold-adapted animals results from an increased epinephrine sensitivity. (2). To our knowledge this is the first demonstration of non-shivering heat regulation of this magnitude. The response is augmented by adaptation to cold.