In vitro study of the incorporation and transport of nonesterified fatty acids into the phospholipids of the red blood cell membranes of cystic fibrosis patients.

The in vitro incorporation and transport of plasma nonesterified fatty acids into phospholipids of red cell membranes have been studied in cystic fibrosis and healthy children. Red blood cells were labeled in vitro by an active "acyltransferase"-dependent incorporation of radioactively labeled nonesterified fatty acids. [3H]-Palmitic and [14C]-linoleic acid, bound to albumin, have been studied simultaneously because it has been shown before that the concentration of palmitic acid increases and the concentration of linoleic acid decreases both in the plasma nonesterified fatty acid fraction and in the various phospholipids of the erythrocyte membranes of cystic fibrosis patients. The labeled cells were reincubated in autologous serum and the radioactivity present in the serum lipids and in the major phospholipid fractions of the erythrocyte membranes was measured. A general conclusion is that the in vitro turnover of labeled palmitic and linoleic acids in the phospholipids of the erythrocyte membranes is higher for cystic fibrosis patients than for healthy children. No difference is detectable between the in vitro behaviour of [14C]-linoleic versus [3H]-palmitic acid in cystic fibrosis patients compared with healthy children.