An adipose tissue-specific beta-adrenergic receptor. Molecular cloning and down-regulation in obesity.

Abstract

Clones encoding an atypical &adrenergic receptor were isolated from a rat brown adipose tissue cDNA library.This receptor expressed in Chinese hamster ovary (CHO) cells displays a low affinity for @-adrenergic antagonists and a high affinity for BRL 37344, an agonist that selectively stimulates lipolysis in adipose tissue.The rank order of potency for agonistmediated increases in intracellular cAMP in transfected cells correlates with that for agonist-mediated stimulation of lipolysis in brown adipocytes.Northern blot analysis demonstrates that this receptor subtype is expressed only in brown and white adipose tissue where it represents the predominant &receptor subtype.The amount of atypical &adrenergic receptor present in adipose tissue of obese (fa/fa) Zucker rats is reduced by up to 71% as compared with lean (Fa/Fa) control animals.These findings suggest that a change in the expression of this &adrenergic receptor subtype may play a role in obesity.