Hepatic metabolism of [1-14C]oleate in pregnancy

Livers from normal ad libitum fed nonpregnant and 20 day pregnant rats were perfused in vitro. Uptake and utilization of [1-14C]oleate were measured while the concentrations of free fatty acids in the erythrocyte-free perfusate was maintained at a steady-state level (mean 0.42 +/- 0.03 (S.E.) mM). Pregnancy increased the incorporation by the isolated liver of [1-14C]oleate into perfusate triacylglycerol and cholesteryl esters and into hepatic triacylglycerol, phospholipid, diacylglycerol and cholesteryl esters. The conversion of [1-14C]oleate by the livers into ketone bodies and CO2 was depressed by pregnancy. With pregnancy, the output of the very low density lipoprotein triacylglycerol, cholesterol, cholesteryl esters and phospholipid was increased significantly by the perfused liver. The relative molar composition of the lipid components of the very low density lipoproteins, however, was not altered by gestation, suggesting that the number of particles secreted was increased by pregnancy. The total output of glucose was decreased by livers from pregnant rats. It may be concluded from these data that livers from pregnant rats in late gestation channel fatty acid ([1-14C]oleate) preferentially into products of esterification rather than into products of oxidation.