Prenatal and early postnatal sodium chloride intake modifies the solution preferences of adult rats

To determine whether the concentration of sodium chloride (NaCl) consumed early in life influences the degree of NaCl preference later in life, adult female rats were maintained on diets containing either 0.12, 1.0, or 3.0% NaCl throughout pregnancy; their offspring were continued on these same diets to day 30 of life. Thereafter, all offspring were maintained on a diet containing 1.0% NaCl. At 90 days of age the animals were given a two-bottle preference test between water and various concentrations of NaCl, glucose, and KCl solutions. After preference testing the livers and adrenal glands were removed and weighed. Both male and female offspring raised on the high salt diet showed an elevated preference for NaCl solutions as adults. The effect was nonspecific as the males also exhibited an enhanced preference for glucose solutions. Furthermore, the elevated preferences could be accounted for not by increases in absolute NaCl or glucose intake, but by decreases in water intake. The adrenal gland weights were significantly lower for males in the highest salt group. There is an early period in development during which fluid regulation may be influenced permanently by dietary sodium levels.