Fatty acid synthesis in rat fetuses with intrauterine growth retardation

The effect of uterine artery ligation at 17 days of gestation to induce intrauterine growth retardation (IUGR) on fetal fatty acid synthesis was studied in pregnant rats. Significant impairment in fatty acid synthesis was observed in fetal liver and lung tissues. The specific activity of fatty acids at 19 days of gestation in the liver was lower in the IUGR rats, as compared to controls, 44.6 +/- 13 versus 87.9 +/- 10 cpm/mumol fatty acids (p less than .05). At 21 days of gestation, the specific activity of fatty acids was 40.6 +/- 7.8 as compared to 75.8 +/- 9.8 cpm/mumole in the IUGR and control fetuses, respectively (p less than .05). In lung, the specific activity of fatty acids was 25.7 +/- 5.4 cmp/mumole in IUGR fetuses as compared to 46.6 +/- 9 cpm/mumole in control littermates at 19 days (p less than .05). This difference persisted at 21 days since the specific activity was 32.2 +/- 2.4 in experimental fetuses as compared to 42.6 +/- 3.0 cpm/mumole in controls (p less than .05). Brain and placental tissues demonstrated no statistically significant differences in specific activity at either time in gestation. The total fatty acid content per organ for both liver and lung was also reduced in the IUGR group. Decreased substrate transfer from mother to fetus during placental insufficiency may account for decreased lipogenesis in the IUGR fetus. Brain and placental tissues are spread despite significant compromises in liver and lung capabilities for fatty acid synthesis.