Synthesis of hepatic protein during pregnancy in the rat

The accumulation of hepatic protein during pregnancy in the rat could be the result of a decrease in rate of degradation, an increase in rate of synthesis or both. The purpose of the study was to determine relative rates of synthesis of hepatic protein for pregnant and nonpregnant rats. Pregnant and nonpregnant Sprague-Dawley rats were fed a 20% casein, purified diet from the first day of gestation. On d 19 of gestation the rats were killed. Livers were weighed and assayed for RNA. Relative synthesis rates of hepatic protein were assessed by homologous in vitro cell-free translation. RNA per liver and per g liver and incorporation of labeled leucine into protein per liver and per unit of RNA were greater for the pregnant rats than the nonpregnant rats. In conclusion, accumulation of hepatic protein during pregnancy is at least partially the result of an increase in rate of synthesis.