Plasma Renin Substrate Changes in Experimental Uremia 1

Abstract

Summary And Conclusions

The effect of uremia on plasma renin substrate concentration was investigated in dogs with and without severe renal tubular damage. Dogs with renal tubular damage secondary to ureteral ligation and renal ischemia had markedly elevated plasma renin substrate concentration. These elevations in plasma renin substrate concentration were associated with elevated plasma renin activity. Another group of dogs with uretero-vena cava shunts exhibited the same degree of uremia but had a much smaller increase in plasma renin substrate concentration and no change in plasma renin activity. It is concluded that uremia per se did not stimulate the very large increase in plasma renin substrate concentration observed after renal tubular damage. The increased renin substrate concentration was associated with loss of renal tubular function and cessation of glomerular filtration. These results support the concept that plasma renin substrate concentration may, in part, be controlled by changes in glomerular filtration rate or alterations in renal tubular function.