Alterations in phosphatidylcholine species and their reversal in pulmonary surfactant during essential fatty-acid deficiency

Abstract

Previous studies (Kyriakides, E.C., Beeler, D.A. and Balint, J.A. (1974) Clin. Res. 22, 717a, and Burnell, J.M. and Balint, J.A. (1975) Fed. Proc. 34, 426) have indicated that essential fatty-acid deficiency in rats resulted in significant reduction of palmitate content of lung tissue and lavage phosphatidylcholines. Experiments were, therefore, undertaken to confirm and further characterize these changes and to examine the reversal of these alterations when essential fatty acid deficient rats were fed fat-free diets supplemented with linoleate for 1-14 days. Analysis of the fatty acid composition of liver lipids was used to confirm the presence of essential fatty-acid deficiency in rats that were fed a fat-free diet supplemented with 4% by weight of tripalmitoylglycerol for 14 weeks. Phosphatidylcholines from lung tissue and lavage fluid of essential fatty-acid deficient rats contained significantly less palmitate and significantly more palmitoleate and oleate than those rats receiving linoleate. These changes in fatty acid composition were reflected in a significant reduction of disaturated phosphatidylcholines (predominantly dipalmitoyl) in lung tissue and lavage fluid from essential fatty-acid deficient rats, while the total phosphatidylcholine content remained unchanged. On feeding the diet containing linoleate to the deficient rats, a reversal of these changes began after one day and was nearly complete by 7-14 days.