[Pseudohypoparathyroidism. Disease of the second messenger].

Pseudo-hypoparathyroidism (PHP) is a hereditary disorder with typical dysmorphic signs and symptoms of hypoparathyroidism, which is resistant to parathyroid hormone (PTH). The knowledge of the role of cyclic adenosine monophosphate (cAMP) as a mediator of the action of PTH and the finding, that parathyroid extract in PHP could not stimulate the urinary excretion of cAMP, were necessary to explain the hitherto unknown pathogenesis of Pseudo-hypoparathyroidism. The PTH-sensitive adenylcyclase-system as second messenger is here unable to mediate the action of PTH on its target cells causing disturbances in calcium and phosphorus metabolism.