Lysophosphatidylcholine increases the secretion of cholesteryl ester-poor triacylglycerol-rich lipoproteins by CaCo-2 cells.
To address the effect of lysophosphatidylcholine on triacylglycerol transport in intestine, CaCo-2 cells, grown on semipermeable supports, were incubated with lysophosphatidylcholine solubilized in 1 mM taurocholate. [14C]Palmitoyllysophosphatidylcholine was readily taken up and incorporated predominantly into cellular phospholipids, particularly phosphatidylcholine. Twenty-five percent of the label was found in triacylglycerols. Compared with labelled cellular phospholipids, labelled triacylglycerols were preferentially secreted. Lysophosphatidylcholine caused a profound decrease in cholesteryl ester synthesis and secretion, whereas cellular triacylglycerol mass and triacylglycerol synthesis and secretion were increased. The effect was more pronounced with oleoyllysophosphatidylcholine than with either palmitoyl- or stearyl-lysophosphatidylcholine. Lysophosphatidylcholine increased the secretion of immunoreactive and newly-synthesized apoprotein B (apoB) without altering the rate of apoB synthesis. Thus, luminal lysophosphatidylcholine and/or its uptake decreases cholesterol esterification and secretion, but increases triacylglycerol synthesis and secretion, triacylglycerol mass accumulation and the secretion of apoB by CaCo-2 cells.
Field
F J
FJ
University of Iowa, Department of Internal Medicine, Iowa City 52242.
Born
E
E
Chen
H
H
Murthy
S
S
Mathur
S N
SN
D000818:Animals; D001055:Apolipoproteins B / Q000096:biosynthesis*; D002460:Cell Line; D005227:Fatty Acids / Q000032:analysis; D007413:Intestinal Mucosa / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D014280:Triglycerides / Q000096:biosynthesis*
D001055:Apolipoproteins B; D005227:Fatty Acids; D008244:Lysophosphatidylcholines; D014280:Triglycerides