Concentration of transcortin in the pregnant rat and its foetuses.

The concentration of transcortin in serum from foetal, neonatal, pregnant and lactating rats was measured by a single radial immunodiffusion method. A decrease in transcortin concentration in sera from foetuses and pregnant rats occurred starting on days 19 and 20 of pregnancy respectively. A more pronounced fall in transcortin concentration in foetal and maternal serum was observed after treating pregnant rats with dexamethasone. These results suggest that corticosterone may be responsible for the observed changes in transcortin concentration.