Fever and the acute elevation in whole-body thermogenesis induced by lateral hypothalamic lesions

Three studies investigated the role of fever in the acute elevation of heat production induced by lateral hypothalamic (LH) lesions and the mechanisms by which this thermogenic response can be attenuated by reductions in body weight. In Study 1, reducing the weights of rats prior to lesioning the LH attenuated both the usual postlesion fever and elevation in thermogenesis. In Study 2, blocking prostaglandin synthesis with indomethacin likewise blunted both the lesion-induced fever and thermogenesis. In Study 3, treating already weight-reduced rats with indomethacin attenuated, but still failed to eliminate, the lesion-induced fever. Together, these results suggest that both the fever and increased thermogenesis induced by LH lesions are mediated, at least in part, by prostaglandin mechanisms which themselves are influenced by body energy status.