Distribution of unsaturated fatty acids in phospholipids of arteries from nonpregnant, pregnant and fetal sheep

Normal ovine pregnancy is associated with elevated levels of circulating vasodilator prostaglandins (PGs) and increases in PG production by uterine and systemic arteries. We hypothesized that the availability of fatty acid substrate may regulate PG production in vasculature from nonpregnant, pregnant and fetal sheep. In pregnant sheep, levels of arachidonic acid (20:4ω6), the immediate PG precursor, were significantly lower in phospholipids from uterine versus systemic (renal) arteries. Although linoleic acid (18:2ω6), the primary arachidonic acid precursor, was elevated (p < 0.001) in uterine arteries during pregnancy, levels in systemic arteries were decreased. Levels of ω3 polyunsaturated fatty acids (PUFAs) also were increased (p < 0.001) in both uterine and systemic arteries during pregnancy. In fetal-placental arteries, the levels of arachidonic and linoleic acid were 50 and 90% less, respectively, than that in maternal arteries. We conclude that during ovine pregnancy vascular prostanoid production may be regulated, in part, by the availability of fatty acid precursors.