Role of beta1- and beta3-adrenoceptors in the regulation of lipolysis and thermogenesis in rat brown adipocytes

The respiratory and lipolytic effects of adrenergic agonists and antagonists were investigated in rat brown adipocytes to determine the physiologic functions of beta1-, beta2- and beta3-adrenoreceptors (ARs). Beta-agonists stimulated both lipolysis and respiration 8-10 times above basal levels. Norepinephrine was able to stimulate lipolysis and respiration through beta1-ARs while beta2-ARs played only a minor role in this mechanism. Meanwhile, beta3-ARs may represent the physiological receptors for high norepinephrine concentrations.