Effect of prolactin on the water-salt balance in rat females in the model of cholestasis of pregnancy.

We studied the possibility of prolactin involvement in the regulation of water-salt metabolism in female rats in the model of cholestasis of pregnancy. For simulation of the prolactin level during pregnancy, hyperprolactinemia was simulated by transplantation the pituitary under the renal capsule of the recipient; for modeling cholestasis of pregnancy, a combination of induced hyperprolactinemia and bile duct obstruction was used. Diurnal diuresis, expression of aquaporin 1-4 mRNA in the renal medulla, glomerular filtration rate, and diurnal sodium excretion were evaluated in these models. Diuretic and natriuretic effects of prolactin in the model of cholestasis of pregnancy were demonstrated. These data and the fact that prolactin has no effect on glomerular filtration rate and aquaporin expression suggest that prolactin modulates activity of sodium transporters in the kidney.