Stimulation of Enzyme Activity by Parathyroid Hormone

Received for publication 26 October 1976 and in revised form 24 January 1977. INTRODUCTION The fat cell adenylate cyclase is a plasma membrane-bound enzyme which is supposed to play a central role in the stimulation of lipolysis by hormones (1). The rat fat cell enzyme reacts to a variety of hormones including catecholamines and peptide hormones such as ACTH, glucagon, and secretin (2-4). By contrast, only catecholamines have been found to be capable in activating the human enzyme system (5-10). In this communication it is shown that parathyroid hormone (PTH)' can activate the adenylate cyclase system of human fat cell ghosts via binding to an individual receptor separable from adrenergic receptor sites.