Activation of phosphorylase in toad bladder and mammalian kidney by antidiuretic hormone

¹ Laboratory of Kidney and Electrolyte Metabolism, National Heart Institute, National Institutes of Health, Bethesda, Maryland

An increase in phosphorylase activity has been demonstrated in the intact urinary bladder of the toad and in slices of rabbit renal medulla and dog renal cortex and medulla incubated in vitro with vasopressin. A similar response occurred in the toad bladder incubated with adenosine-3',5'-monophosphate (cyclic-3',5'-AMP). Phosphorylase activation in the bladder was also produced by incubation with oxytocin or protopituitrin, but not by incubation with ACTH or epinephrine. The metabolic significance of hormone-induced phosphorylase activation is unclear. However, since activation of phosphorylase is a characteristic tissue response to hormones that act through cyclic-3',5'-AMP, the present observations support the suggestion that vasopressin alters the permeability to water of the urinary bladder of the toad and mammalian kidney through a pathway involving stimulation of the production of cyclic-3',5'-AMP.