Trans fatty acids: transport and positional specificity in rat placental lecithin.

Differences in positional incorporation of trans and cis isomers of octadecenoic and octadecadienoic acids in placental lecithin of rats was demonstrated. A 14C-labeled albumin complex of elaidic, oleic, linoelaidic, or linoleic acid was injected into the jugular vein of pregnant rats. 6 h later 45-64% of the total radioactivity in placental lipids was found in phospholipids (PL), with a major portion of the label incorporated into choline phosphoglycerides (CPC). Following hydrolysis of placental CPC by phospholipase A2, distribution of radioactivity within isolated fatty acids and lysolecithin suggested preferential incorporation of t,t-18:2 at position 2 and a nearly equal distribution of t-18:1 at positions 1 and 2.