[Ammonia metabolism of liver of the fetus induced experimental IUGR in rats--in respect of the enzymes in pyrimidin biosynthesis and urea cycle system].

Experimental intrauterine growth retarded fetuses (IUGR) were produced in rats. A cesarean section was performed on the 20th day of pregnancy. The enzymes and intermediate metabolite of pyrimidine biosynthesis (de novo pathway) and ammonia metabolism were studied in the fetal rat liver of IUGR and control group. The level of activity of carbamyl phosphate synthetase I(CPS I) in IUGR's liver was significantly lower than that of the control group. The activities of carbamyl phosphate synthetase II(CPS II) and aspartate transcarbamylase (ATC) in IUGR's liver were significantly higher than those of the control group. The content of orotate in IUGR's liver was significantly lower than that of control group, though the activities of CPS II and ATC were increased.