Dissociation of circulating renin and erythropoietin in rats.

Renin and erythropoietin activities were measured in the plasma of 110 rats exposed to various conditions designed to dissociate the two renal "hormones." In acute experiments, intraperitoneal injection of polythiazide increased renin activity but did not change erythropoietin activity; exposure to low oxygen tension increased erythropoietin activity and caused an insignificant decrease in renin activity. In chronic experiments, salt restriction or the combination of salt loading and desoxycorticosterone for 2 weeks increased or decreased renin activity, respectively, without changing erythropoietin activity. The combination of chronic salt loading and acute hypoxia reduced renin activity and increased erythropoietin activity. In the final experiment, intraperitoneally injected cobaltous chloride acutely increased erythropoietin activity without markedly altering renin activity. Without contributing to the solution of the problem of the cell origin of erythropoietin, the present study clearly indicates that the secretion of renin and erythropoietin can be dissociated. ADDITIONAL