Adrenal cortex and renal pressor function.

Abstract

The pressor response of the nephrectomized rat to the injection of kidney extracts and to a renal graft, was used as an index of the renal content and secretion of pressor substances during adrenal insufficiency or treatment with corticosteroids. Adrenalectomy caused an elevation of both content and secretion, which was best demonstrated after two to three weeks of maintenance therapy. Treatment with cortisone and cortisol decreased slightly but significantly the secretion of pressor substances without altering renal content. ACTH had no effect on either function. Sequential studies of content and secretion of pressor substances during treatment with DCA plus salt showed first a rapid disappearance of prossor activity from renal vein blood followed by a decrease in renal content to near zero levels; DCA without excess salt elicited the same effects but more gradually; administration of 1% saline alone decreased secretion without altering content. It is concluded that salt active corticosteroids specifically inhibit the formation and secretion of renal pressor substances and that determination of the index of secretion constitutes a more reliable and sensitive indicator of the renal pressor function than determination of the pressor activity in kidney extracts.