Regional renal blood flow in ewes.

Regional blood flow to the kidneys was measured in 6 ewes by injecting carbonized microspheres (15 micrometer +/- 5) labeled with 85Sr into the left ventricle. There was no significant (P greater than 0.25) difference in the mean arterial pressure before and after injection of the microspheres. Normal values of blood flow to the outer cortex, inner cortex, and medulla were determined. The blood flow to the outer cortex was highest, followed (in a decreasing order) by the inner cortex and the medulla. Significant differences in blood flow were not detected between dogs, and sheep. The microsphere technique, based on Fick's principle, requires minimum instrumentation and does not require surgical manipulation of the kidney. The objective of the present experiment was to determine and compare the blood flow to regions of the ovine kidneys.