Incorporation of exogenous unsaturated fatty acids in mouse jejunal explants

Esterification processes of oleic (OA), linoleic (LA) and arachidonic acids (AA) were investigated in mouse jejunal explants with some references to age (2.5, 12 and 21 months) of the animal tissue donors. Explants were incubated either for 15 min in a stirred medium enriched with lipids or cultured for 15 min in Falcon dishes in a culture medium enriched with lipids, then for 6 h in a lipid-free medium. In 2.5-month-old mice, released lipoprotein OA secreted in the medium was especially integrated into the triacylglycerols, while LA was significantly integrated into glycerophospholipids. Triacylglycerol formation from released AA was always significantly lower than from OA. With increasing age of the animals, decreasing amounts of OA appeared in triacylglycerols. The preferential association of OA with triacylglycerols observed in jejunal explants coincided with a preferential esterification of OA observed with the enzymatic assays. The utilization of the arachidonoyl-coenzyme A by the microsomal acyltransferase was low at all ages.