Demonstration of a humoral inhibitor of the Na+-K+ pump in some models of experimental hypertension.

Abstract

We have previously shown that ouabaln-sensitive M Rb uptake, a measure of Na + -K + pump activity, is decreased in the blood vessels of dogs with one-kidney, one wrapped hypertension and rats with onekidney, DOCA, saline hypertension. We here extend the study to rats with one-kidney, one clip and reduced renal mass-saline hypertension. We also assayed supernates of boiled plasma from three of these models for ouabain-sensitive u Rb uptake suppressing activity. Finally, we examined the influence of the anteroventral third ventricle (AV3V) lesion in the rat on vascular pump and plasma supernate activities. We found that ouabain-sensitive M Rb uptake is suppressed in the tail arteries of rats with one-kidney, one clip and reduced renal mass hypertension and that plasma supernates from these rats and from dogs with one-kidney, one wrapped hypertension suppress M Rb uptake when applied to tail arteries from normal rats. We also found that, in the volume-expanded state, rats with AV3V lesions had higher vascular ouabain-sensitive M Rb uptake than rats with sham lesions and evidence for decreased inhibitory activity of the plasma. These findings suggest that reduced vascular Na + -K + pump activity is common to several models of experimental hypertension and that this defect results from a heat-stable ouabain-like agent in plasma that originates in or is influenced by the AV3V area of the brain. (Hypertension 3 (suppl II): II-96-II-101, 1981)