297 EFFECT OF INTRAUTERINE GROWTH RETARDATION (IUGR) ON FATTY ACID SYTHESIS

Abstract

The effects of IUGR on fetal triacylglycerol fatty acid (FA) synthesis was studied in 26 pregnant rats by 3H2O injection. IUGR was induced by uterine artery ligation on one horn and litters from the opposite horn served as controls. The specific activity of FA at 19 days of gestation in the liver was lower in the IUGR fetus, as compared to controls, 44.6±13 vs. 87.9±10 cpm/μmole FA, (p<.05). At 21 days of gestation, the specific activity of FA remains lower in the IUGR group, (40.6±7.8 vs. 75.8±9.8 cpm/μmole p<.05). In lung, the specific activity of FA was 25.7±5.4 cpm/μmole in IUGR fetuses as compared to 46.6±9 cpm/μmole in controls at 19 days (p<.05). This difference persisted at 21 days (32.2±2.4 vs. 42.6±3.0 cpm/μmole in IUGR and controls, respectively, p<.05).The total fatty acid content per ogran for both liver and lung was also reduced in the IUGR group. However, when expressed per unit organ weight, (gram) the IUGR fetuses have a significantly higher FA content at 21 days than the controls. This observation is probably related to a proportionally greater reduction in the accretion rates of substrates other than fat during growth. The data indicates that fetal growth retardation induced by placental vascular insufficiency is associated with reduced fat synthesis probably on the basis of reduced placental transfer of precursors for fatty acid synthesis. Similar phenomenon may be present in human IUGR infant.