Quantitative assay and disappearance rate of circulating renin

Abstract

In isovolemic cross-circulation experiments, a nephrectomized donor rat, into which various doses of hog renin were injected, was connected to a nephrectomized indicator rat. The blood pressure increase thus produced in the indicator rat was compared with the blood pressure response obtained during cross circulation using either intact normotensive or renal hypertensive rats as donor animals. An exponential dose-response relationship was found between hog renin injected into a nephrectomized donor and the blood pressure increase of the indicator rat. Using the cross-circulation technique, the disappearance rate of endogenous reninlike material in the blood of donor animals and of exogenous renin injected into nephrectomized donor animals was examined. If an intact normotensive animal or a unilaterally nephrectomized hypertensive animal is totally nephrectomized, reninlike material disappears from the blood within 1 hr. In renal hypertensive rats with an untouched contralateral kidney which have a higher concentration of reninlike material in the blood, it takes about twice the normal time until reninlike material disappears from the blood after nephrectomy. The increased and prolonged blood pressure response of the nephrectomized animal to renin is not connected with a prolonged persistence of renin in the blood.