Influence of dietary fats on pancreatic phospholipids of chronically ethanol‐treated rats

Abstract

Male rats were given liquid diets by pair-feeding for 24-30 days, and phosphatidylinositols in pancreas were analyzed as derivatives of diacylglycerols and fatty acids. Addition of arachidonic acid or changing the fat component (35 energy %) in the liquid diet from olive oil/corn oil to oil from Borago officinalis, which contains 22% gamma-linolenic acid, increased the fraction of arachidonoyl-containing species. This fraction was decreased by more than 50% by substituting ethanol for 36 of the 47 energy% provided by carbohydrate. A smaller difference between ethanol-fed and control rats was seen in the composition of phosphatidylcholines and phosphatidylethanolamines. There was no difference in the composition of phosphatidylinositols when fat, instead of ethanol, was used to substitute the 36 energy % in the diet containing olive oil/corn oil. Substituting ethanol for 28 of 35 energy% provided by fat as corn oil in a liquid diet had no effect on the fraction of arachidonoyl-containing species. The results indicate that the effect of ethanol on phosphatidylinositols in pancreas is not due to a deficiency of arachidonic acid, and that the effect of the ethanol-containing diet is not due to the lowered carbohydrate content. However, high contents of fat or of ethanol appear to be necessary for the effect.

Decreased content of arachidonoyl species of phosphatidylinositol phosphates in pancreas of rats fed on an ethanol-containing diet

“…The differences in Ptdlns composition between ethanol-fed and control rats were of the same type as previously observed by analysis of the diacylglycerols released by phospholipase C [1,4]. Thus the abundance of arachidonoyl-containing species in the ethanol-treated rats was about half that in the controls.…”

“…spectrum were deduced from the gas chromatographic analyses of fatty acid methyl esters obtained by trans-esterification and from previous results [2][3][4]. The variation in determined composition was clearly higher for PtdIns4P than for PtdIns (4,5)P2. This was probably due to the additional material present in the PtdIns4P fraction, giving peaks in the f.a.b.…”

“…The reason for this effect of ethanol is not known. The possibility that peracetic acid formed from ethanol might inhibit arachidonic acid incorporation [14] would not explain why other phospholipids were unaffected [1,4].…”

“…The composition of phosphatidylinositol (Ptdlns) in the pancreas has been found to be markedly changed in rats fed on ethanol-containing diets [1][2][3][4]. The content of arachidonoylcontaining species is decreased by about 50%.…”

“…The content of arachidonoylcontaining species is decreased by about 50%. Attempts to prevent or mimic this effect by pharmacological [2] or dietary [4] means have not been successful, and the reason for the change and its possible consequences are not known. It might conceivably be related to the mechanism behind alcohol-induced chronic pancreatitis, since Ptdlns is a constituent of the cell membranes, acts as an anchor for membrane-bound enzymes [5] and serves as a precursor for the phosphorylated forms of Ptdlns, PtdIns4P…”