Alteration of erythrocyte lipid composition following total parenteral nutrition in the rat.

Rats were infused continuously for 7 days with a complete total parenteral nutrition (TPN) solution in which 27.5% total calories were given as a parenteral lipid emulsion containing soybean oil (Liposyn) or safflower oil (Intralipid) emulsified with egg phospholipid (PL). Compared to sham-operated rats fed chow, the erythrocyte membranes from rats given TPN with lipid emulsion had increased cholesterol and PL but normal molar cholesterol:PL ratios. The fatty acid changes in sphingomyelin and phosphatidylcholine, in particular, suggested replacement of endogenous PL with the exogenous egg PL infused with the emulsion. The changes in membrane lipid composition were accompanied by greater resistance of the cells from rats given TPN to osmotic lysis in vitro.