Abstract
The changes in the number and affinity of binding sites in the β-adrenergic receptors of rat white adipocytes after cold exposure were studied with the aid of (-)-[3H] dihydroalprenolol. One day cold exposure did not change the number and affinity of binding sites in β-adrenergic receptors. Chronic exposure of rats to cold (5°C) for 1 and 4 weeks significantly decreased the affinity of β-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°C) remained for 18 hr after these animals were transferred to a warm environ-ment of 25°C. The decreased affinity of binding sites in β-adrenergicreceptor induced by cold acclimation could not explain the enhanced metabolic response of cold-acclimated animals to noradrenaline.
