Mechanism of the redistribution of renal cortical blood flow during hemorrhagic hypotension in the dog.

Studies were performed to define the mechanisms involved in the redistribution of renal cortical blood flow to inner cortical nephrons which occurs during hemorrhagic hypotension in the dog. The radioactive microsphere method was utilized to measure regional blood flow in the renal cortex. Renal nerve stimulation decreased renal blood flow 40% but had no effect on the fractional distribution of cortical blood flow.

Uterine blood flow and uterine renin secretion.

Experiments were carried out in pregnant nephrectomized rabbits to determine the relationship between uterine blood flow and uterine renin secretion. Uterine blood flow was measured by the percentage distribution of radioactive microspheres injected into the left ventricle which lodged in uterus and placenta, and cardiac output was measured by dye dilution. In 40 animals, 24 hr after nephrectomy, uterine blood flow was 4.

The effect of bradykinin on proximal tubular sodium reabsorption in the dog: evidence for functional nephron heterogeneity.

In a previous study we have found that acetylcholine, a renal vasodilator, inhibits fractional and absolute reabsorption of sodium in the proximal tubule of the dog. To delineate whether this effect on proximal tubular sodium reabsorption was related to alterations in renal hemodynamics or to a direct tubular action of the drug, free-flow micropuncture studies were performed in the dog in which the tubular fluid to plasma inulin ratio and nephron filtration rate were determined before and during the administration of a structurally different renal vasodilator, bradykinin. This agent increased sodium excretion from 12 to 96 muEq/min and decreased total kidney filtration fraction from 0.

Effect of renal vasodilatation on the distribution of cortical blood flow in the kidney of the dog.

Studies were performed to evaluate the validity of using the radioactive microsphere technique to measure regional blood flow in the renal cortex. A technique was developed in which the renal cortex was divided into four equal zones, and the fractional and absolute distribution of blood flow in these zones was determined. It was consistently found that approximately 70% of the renal blood flow was distributed to the two outer cortical zones with the remaining 30% going to the two inner cortical zones.

Toxemia of pregnancy in sheep: a clinical, physiological, and pathological study.

Toxemia was induced in 13 of 20 pregnant ewes by the stress of a change in environment and food deprivation late in pregnancy. Of the toxemic ewes, eight developed prominent neurological findings with convulsions, motor weakness, and blindness, whereas five ewes developed azotemia without neurological signs. Proteinuria and azotemia occurred in all but one of the toxemic animals.