INTESTINAL LIPID ESTERIFICATION AND AGING IN MICE AND RATS

The effects of aging on lipid absorption, particularly on fatty acid g lycerophospholipid and triacylglycerol esterification, were investigat ed in 2.5-,12- and 24-month-old mice and rats. Two intestinal mucosa m icrosomal enzymes, involved in the dietary fatty acid absorption, were assayed:acylCoA:2-monoacylglycerol acyltransferase and acylCoA:1-lyso phosphatidylcholine acyltransferase. In both mice and rats, the activi ties of both enzymes varied with the nature of the acyl-CoA. Indeed ac ylCoa:2-monoacylglycerol acyltransferase activities were significantly higher with oleoyl-CoA and linoleoyl-CoA than with palmitoyl-CoA and arachidonoyl-CoA, while acylCoA:1-lysophosphatidylcholine acyltransfer ase activities were highest with arachidonoyl-CoA. AcylCoA:2-monoacylg lycerol acyltransferase activity did not decrease significantly with a ging in mice or rats, whatever the acyl-CoA used. In contrast, acylCoA :1-lysophosphatidylcholine acyltransferase activity in the 24-month-ol d rats was significantly lower (-47 %) than in 2.5-month-old rats, wit h oleoyl-CoA, linoleoyl-CoA and arachidonoyl-CoA. Simultaneously we ob served that less glycerophospholipid esterification of oleic and linol eic acid occurs in older rats than in 2.5-month-old rats. Copyright (C ) 1997 Elsevier Science Inc.