Differences in Levels of Circulating Vasopressor Materials in Dogs with Acute and Chronic Renal Hypertension. ∗

Abstract

Summary

Small amounts of plasma from dogs with acute renal hypertension were shown to contain easily detectable amounts of a vasopressor substance for approximately the first 2 weeks after renal artery constriction. This is consistent with the view that a humoral mechanism plays a role in the origin of the high blood pressure. With our technique the vasopressor material tended to disappear from the blood between 1 and 3 weeks after renal artery clamping and thereafter all assays of plasma for vasopressor activity were negative. Thus, in the dog as in the rat, and for reasons not clear, the acute and chronic stages of experimental renal hypertension differ sharply in respect to recovery of circulating pressor substance. While this finding does not necessarily exclude a humoral system from participating in the pathogenesis of chronic renal hypertension, it indicates that the level per se of circulating vasopressor material is not the critical factor in sustaining the high blood pressure in this stage.