Leukocyte effects on the vascular resistance and glomerular filtration of the isolated rat kidney at normal and low flow states.

Because of their large volume and high internal viscosity, leukocytes may obstruct capillary blood flow, particularly in low flow states. In the present study rat kidneys were isolated and perfused with a cell-free colloid solution. The urine production was continuously measured and samples were taken for determination of inulin clearance. In this way changes in glomerular filtration rate (GFR) and tubular reabsorption (TR) could be followed before, during, and after a bolus injection of leukocytes separated from whole blood. The experiments showed that leukocyte infusion caused a sustained increase of the renal vascular resistance, which at low flows ranged from 5 to 20%, whereas at normal flow rates only small and transient increases occurred. The passage of a leukocyte bolus caused, in addition, a decrease in GFR and to a small degree also in TR. The study indicates that leukocytes may disturb the perfusion of glomeruli and peritubular vessels in low flow states.