Lack of evidence for hepatic control of renal sodium excretion in rats

Three experimental protocols were used: a) normal and partially hepatectomized rats were expanded with isotonic saline; b) normal rats were expanded with isotonic saline; b) normal rats were infused with hypertonic saline (5%), either by the femoral or portal vein and c) hypertonic saline was sequentially and alternatively infused into normal rats via portal and femoral veins. All the experiments were made under anesthesia. Inulin clearance and absolute and fractional urinary sodium and potassium excretion were measured. Multiple analysis of variance was made to compare normal and partially hepatectomized rats, as well as portal and femoral infusions made either in the same or in different animals. In none of these experiments it was possible to demonstrate an effect of the liver in enhancing the natriuresis induced by saline infusions.