Modulation of polyunsaturated fatty acid content of triglycerides in rat pre-adipocytes in culture.

Rat peri-renal and epididymal pre-adipocytes in culture undergoing triglyceride (TG) accumulation were incubated with oleic (18:1), linoleic (18:2), alpha-linolenic (18:3 omega 3), arachidonic (20:4) and 4,7,10,13,16,19-docosahexaenoic (22:6 omega 3) acids in the presence of 0.8 microM insulin. The fatty acids were incorporated in cellular TG with relative enrichments over control from 1.4-fold for 18:1 to greater than 40-fold for 18:3 omega 3. Greater than 80% of fatty acids taken up were incorporated into cellular TG. The balance was distributed, in decreasing amounts, into phospholipids, unidentified intracellular constituents, and ketone bodies. The P/S ratio of cellular TG was at least an order of magnitude lower than that of the external milieu for both cell types and for all treatment groups, including controls. Doubling the concentration of treatment fatty acid increased its incorporation into cellular TG. However, it did not affect the accumulation of the other fatty acids in TG. Epididymal cells consistently acquire a higher proportion of treatment fatty acids in cell TG than peri-renal cells. Pre-adipocytes with polyunsaturated fatty acids (PUFA)-enriched TG is a potential model for the study of PUFA metabolism in these types of cells.