Changes in adipocyte beta-adrenergic receptor of cold-acclimated rats

The changes in the number and affinity of binding sites in the beta-adrenergic receptors of rat white adipocytes after cold exposure were studied with the aid of (p)-[3H]dihydroalprenolol. One day cold exposure did not change the number and affinity of binding sites in beta-adrenergic receptors. Chronic exposure of rats to cold (5 degrees C) for 1 and 4 weeks significantly decreased the affinity of beta-adrenergic receptors without any alteration in the number of binding sites. Such changes in the binding affinity observed in cold-acclimated rats (4 weeks, 5 degrees C) remained for 18 hr after these animals were transferred to a warm environment of 25 degrees C. The decreased affinity of binding sites in beta-adrenergic receptor induced by cold acclimation could not explain the enhanced metabolic response of cold-acclimated animals to noradrenaline.