Influence of protein deficiency in rats on hormonal status and cytoplasmic glucocorticoid receptors in maternal and fetal tissues.

The influence of dietary protein deficiency on maternal plasma corticosterone and progesterone levels as well as on maternal and fetal liver and lung cytoplasmic glucocorticoid receptors has been studied in Sprague-Dawley rats during the last 3 days of gestation. Plasma corticosterone levels of control but not protein-deficient rats increased on days 20 and 21 of gestation; corticosterone levels of protein-deficient rats decreased on day 21 of gestation. Maternal adrenalectomy caused only a moderate decrease in corticosterone levels in both groups of pregnant rats. Fetal corticosterone levels of the two groups of rats were similar. Progesterone levels were consistently lower in protein-deficient than in control animals from day 20 of gestation until 2-12 h after parturition. There were no differences in the binding of [3H]dexamethasone to liver cytosol of non-pregnant control and protein-deficient rats. However, receptor levels were lower in pregnant controls than in pregnant protein-deficient rats. Maternal protein deficiency led to an increase in fetal liver glucocorticoid receptor levels but exerted no significant effect on receptor levels in fetal lung. It is suggested that lower levels of plasma corticosterone and progesterone and high levels of liver glucocorticoid receptors in protein-deficient rats might be related to some of the adverse consequences of maternal malnutrition on fetal development.