EFFECT OF RENIN ON EXTRARENAL ERYTHROPOIETIN PRODUCTION

  • 1 January 1976
    • journal article
    • research article
    • Vol. 88  (5) , 707-715
Abstract
Extracts containing renal erythropoietic factor (REF) and others containing renin reportedly enhance erythropoietin (Ep) titers in the plasma of hypoxic nephrectomized rats. The mechanism by which renin increases Ep production in the anephric rat was studied. Injection of a renal extract containing renin significantly raised the blood pressure of anephric rats, and when it was injected just prior to exposure to hypoxia and 15 h postnephrectomy, the resultant plasma Ep level exceeded that observed in rats exposed to the same hypoxic conditions immediately postnephrectomy. Rats made hypoxic 15 h after nephrectomy, but not given renin, had plasma Ep levels lower than those of anephric rats made hypoxic immediately postoperatively. When renin was injected immmediately after nephrectomy or into normal rats, it failed to stimulate Ep production. When diazoxide was injected with the renin extract into hypoxic nephrectomized rats, the vasopressor effect of renin was abolished for 4 h, and the plasma Ep levels were significantly lower than those of hypoxic nephrectomized animals injected only with renin. Injection of angiotensin II into anephric, hypoxic rats had an effect comparable to that of renin on extrarenal Ep production. REF was not detectable in the renin preparation. Renin and angiotensin probably increase extrarenal Ep production by causing vasoconstriction and consequently hypoxia in extrarenal sites of Ep production. Plasma Ep levels of rats, injected with renin and made hypoxic 15 h postnephrectomy, are higher than those previously reported to occur in anephric rats.