Blunted plasma cyclic adenosine monophosphate response to isoproterenol in pseudohypoparathyroidism

Plasma cAMP, serum glucose, and cardiovascular responses to isoproterenol infusion were examined in seven normal subjects and seven patients with pseudohypoparathyroidism (PHP), type I (three with deficiency of the hormone receptor-cyclase coupling protein (N-protein) and four who were N-protein replete). Although plasma cAMP responses were blunted in both subgroups of PHP patients, the cardiovascular and glucose responses to isoproterenol were normal. We conclude that the blunted plasma cAMP response to isoproterenol in PHP does not depend on deficient N-protein coupling of adenylate cyclase to the beta-adrenergic receptor and that the cardiovascular and glucose responses to isoproterenol are not reflected in changes in plasma cAMP.