AJP - Renal Physiology, Vol 250, Issue 1 40-F46, Copyright © 1986 by American Physiological Society
Effects of blood viscosity on plasma renin activity and renal hemodynamics
S. Simchon, R. Y. Chen, R. D. Carlin, F. C. Fan, K. M. Jan and S. Chien
The effects of alterations in apparent blood viscosity on renal
hemodynamics and plasma renin activity (PRA) were studied in dogs
anesthetized with sodium pentobarbital. Blood viscosity was altered
isovolemically either by changes in hematocrit (Hct) or by an increase in
plasma viscosity (dextran administration). Arterial blood pressure and
renal blood flow (RBF) remained relatively constant when apparent blood
viscosity was elevated by changes in Hct or plasma viscosity. Thus the
hyperviscosity of blood was associated with a decrease of renal vascular
hindrance, resulting in an essentially unchanged renal flow resistance. The
decrease in renal vascular hindrance may result from renal vasodilation. In
hyperviscosity induced with dextran, the increase in PRA correlates
linearly with the decrease in renal vascular hindrance, with a coefficient
of correlation of 0.968 (P less than 0.005). The increase in PRA that
resulted when Hct was raised from 25 to 55% also can be correlated linearly
with the decrease in renal vascular hindrance, with a coefficient of
correlation of 0.953 (P less than 0.005). These results suggest that the
decrease in renal vascular hindrance in response to a rise in apparent
blood viscosity leads to an increase in PRA.
