Metabolic adjustment induced by exposure to elevated ambient temperature is impaired in rats bearingt lesions in the preoptic area

RESUMO

Metabolic adjustment was studied in rats with bilateral electrolytic lesions in the preoptic area which were exposed to heat (34-C) anda to normal temperature (25-C) for 60 days. The metabolic rate measured at neutral temperature (29-C) in preoptic-lesioned rats living at 25- or 34-C was reduced to 80% the rate of sham-operated controls. The increase in metabolic rate induced by heat (30 min at 34- or 37-C) in preoptic-lesioned rats, living at 25-C, was markedly reduced to 10% the rate of sham-operated controls living at 25-C. In preoptic-lesioned rats, the increased metabolic rate induced by heat exposure (34- or 37-C) was impaired, regardless of the living ambient temperature (25- or 34-C) of the animal. These data demonstrate the participation of the preoptic area in heat-induced invreased oxygen consumption and provide additional evidence for its role in the integration of thermal imputs with energy-linked metabolic processes