APOLIPOPROTEIN SECRETION AND LIPID-SYNTHESIS - REGULATION BY FATTY-ACIDS IN NEWBORN SWINE INTESTINAL EPITHELIAL-CELLS

The IPEC-1 newborn swine intestinal epithelial cell line was used to d etermine the effects of the uptake of various fatty acids on the secre tion of apolipoprotein (ape) B and apo A-I, as well as triglyceride an d phospholipid. Long-chain saturated fatty acids were taken up and sti mulated triglyceride synthesis, and palmitic (16:0) and stearic (18:0) acids also stimulated phospholipid synthesis. However, these fatty ac ids did not enhance triglyceride, phospholipid, or apo B or apo A-I se cretion. Oleic acid (18:1) was the most effective of all fatty acids t ested in stimulating triglyceride synthesis and the secretion of trigl yceride, phospholipid, and apo B. Linoleic (18:2) and linolenic (18:3) acids were no more effective than long-chain saturated fatty acids in stimulating these processes. With saturated fatty acids, apo A-I foll owed the same secretory pattern as apo B. However, among the unsaturat ed-fatty acids, oleic acid was the least effective and linolenic acid was the most effective in stimulating apo A-I secretion. Basolateral s ecretion of lipid and apolipoproteins by differentiated IPEC-1 cells i s differentially regulated by apical exposure to fatty acids.