Tissue blood flow in rat kidneys by hydrogen desaturation

Abstract

The effects of time after commencing procedure, body temperature, and electrode location upon the observed rate of blood flow in rat kidney cortex, as determined by the hydrogen desaturation method, were studied. The rate of blood flow (in ml/min. per 100 g tissue) increased significantly from a mean of 262.8 [plus or minus]45.5 (SD) at 10-15 min. to 338.9 [plus or minus] 32.1 (SD) at 2-3 hr. after the procedure was begun. Lowering the body temperature by 1[degree]C intervals from 38.0-38.5[degree] C to 32.0-32.5[degree] C resulted in significant decreases in the rate of cortical blood flow despite the opposing effect of time. No significant differences were observed between the rates of flow at 2 sites 5 mm apart in the kidney cortex when time and temperature were held constant It is concluded that for tissue blood flow measurements by hydrogen desaturation to be comparable in a series of rats, the determinations should be made at the same body temperature and at the same time relative to beginning the procedure.