Effect of phospholipid acyl chain modulation on vitamin E incorporation into pulmonary artery endothelial cell membranes

Incorporation of vitamin E (α‐tocopherol) was measured in total membranes of pulmonary artery endothelial cells (PAEC) following treatment with eight synthetic phosphatidylethanolamines (PE) (Palmitoyloleoyl, 16:0–18:1 PE 1 ; distearoyl, 18:0–18:0 PE 2 ; dioleoyl, 18:1–18:1 PE 3 ; stearoyl‐ linoleoyl, 18:0–18:2 PE 4 ; dilinoleoyl, 18:2–18:2 PE 5 ; stearoyl‐arachiod‐nyl, 18:0–20:4 PE 6 ; diarachidonyl, 20:4–20:4 PE 7 ; and stearoyl‐docosahexenoyl, 18:0–22:6 PE 8 ). Endogenous PE content of native membranes was 0.88 ± 0.01 nmol/mg protein. Incorporation of PE irrespective of fatty acid content significantly ( P < 0.02) increased the PE content of total membranes. Vitamin E incorporation in control membranes was 63 ± 9 nmol/mg protein. Incorporations of vitamin E in PE 1 ‐ to PE 7 ‐treated cells were significantly ( P < 0.05) increased compared to controls and were comparable to each other. Vitamin E incorporation into PE 8 ‐treated cells was threefold greater ( P < 0.001) thatn controls and twofold greater ( P < 0.001) than PE 1 ‐ to PE 7 ‐treated cells. Increased PE content results in increased vitamin E incorporation into PAEC membranes irrespective of the fatty acids present on the acyl chain, and maximal incorporation of vitamin E in PE 8 ‐treated cells may relate to the increased carbon chain length rather than to the degree of unsaturation at the sn 2 position. © 1993 Wiley‐Liss, Inc.