Comparative measurements of in vitro thermogenesis of brown adipose tissue from control and cold adapted rats

Heat output and oxygen uptake rates as well as caloric equivalents of O2 were measured in brown fat fragments from cold-adapted and control rats. Resting metabolic rate per unit wet weight was the same in both groups. Submaximal responses to noradrenaline were significantly lower in the cold-adapted than in the control group. Apparent maximal responses were the same for both groups. Caloric equivalents of O2 gave no evidence for anaerobic glycolysis even under conditions of oxygen limitation.