Interaction between catecholamines and vasopressin on renal medullary cyclic AMP of rat.

KUROKAWA, KIYOSHI, AND SHAUL G. MASSRY. Interaction between catecholamines and vasopressin on renal medullary cyclic AMP of rat. Am. J. Physiol. 225(4) : 825-829. 1973.-The effects of catecholamines, alphaand beta-adrenergic blockers, and the interaction between these agents and vasopressin on cyclic AMP concentration in suspensions of isolated cortical and medullary tubules of rat kidney were evaluated. Vasopressin significantly increased cyclic AMP concentration of medullary tubules while isoproterenol was without effect. However, isoproterenol did moderately stimulate the production of cyclic AMP in dog medullary tubules, indicating a species difference in the response of adenyl cyclase-cyclic AMP system of the renal medulla to isoproterenol. Propranolol did not inhibit the effect of vasopressin to increase cyclic AMP concentration in medullary tubules of rats. Norepinephrine inhibited the vasopressin-stimulated cyclic AMP production. There was a clear relation between this inhibitory effect of norepinephrine and the concentration of vasopressin; for any given concentration of norepinephrine, the concentration of cyclic AMP in medullary tubules was higher with a maximal dose of vasopressin than with a submaximal one. Phentolamine blocked the inhibitory effect of norepinephrine. These data strongly suggest that 1) the antidiuretic effect of intravenous isoproterenol in rats is probably not mediated by the stimulation of adenyl cyclase-cyclic AMP system in the renal medulla, 2) the diuretic effect of norepinephrine is, at least partly, mediated by the inhibition of the effect of vasopressin to increase cyclic AMP generation in the renal medulla.