Effect of subtotal inhibition of liver development on plasma transcortin in chick embryo

Abstract

The relationship between liver weight and the concentration of plasma transcortin (CBG) was investigated in ovo during early chick embryo development. As measured by equilibrium dialysis, corticosterone-binding capacity increased in parallel with liver weight. Early prevention of normal hepatic endodermal cell progression at the 9- to 12-somite stage inhibited liver development subtotally. In the operated embryos, a good correlation between CBG activity in plasma and liver weight was observed: (1) the liver weight of the operated embryos was 78% lower than in the controls of the same age (12 days old) and (2) the CBG activity in plasma compared to the same controls was 85% lower. Previous experiments ( B. Martin and J. M. Gase, 1979, J. Steroid Biochem. 10, 553–556) showed that plasma transcortin is synthesized by embryonic chick liver in vitro. Present data provide evidence that in ovo, the major if not the sole source of plasma transcortin is the liver.