Maternal-fetal exchange during protein malnutrition in the rat. Placental transfer of alpha-amino isobutyric acid.

The influence of protein restriction on the maternal-fetal transfer of nutrients was explored in rats fed a 6% casein diet. At days 20 and 21 of gestation, 1 muCi/100 g of body weight of 14C-alpha-amino isobutyric acid was injected inthe maternal circulation of controls fed a 27% casein diet, and experimental rats. Samples of maternal blood, and one placenta and one fetus were removed from each dam 10, 20, 40 and 60 minutes later. In malnourished dams, the radioactively labeled amino acid had a slower rate of disappearance from the maternal plasma, stayed longer in the placenta and was transported in reduced amount to the fetuses.