Insulin decreases the secretion of apoB-100 from hepatic HepG2 cells but does not decrease the secretion of apoB-48 from intestinal CaCo-2 cells.
We compared the acute effect of insulin on the human colonic intestinal epithelial cell line CaCo-2 and the transformed human hepatic cell line HepG2. Over 24 h, 100 nM and 10 microM insulin significantly inhibited the secretion of apolipoprotein (apo) B-100 from HepG2 cells to 63 and 49% of control, respectively. Insulin had no effect on the secretion of apoB-48 from CaCo-2 cells. There was no effect of insulin on the cholesterol ester or free cholesterol concentrations in HepG2 or CaCo-2 cells. HepG2 and CaCo-2 cells bound insulin with high affinity, leading to similar stimulation of insulin receptor protein tyrosine kinase activation. Protein kinase C or mitogen-activated protein kinase activity in the presence or absence of insulin was not correlated with apoB-48 production in CaCo-2 cells. Therefore, insulin acutely decreases the secretion of apoB-100 in hepatic HepG2 cells, but does not acutely modulate the production or secretion of apoB-48 from CaCo-2 intestinal cells.
Allister
Emma M
EM
Department of Nutrition, Dietetics and Food Sciences, Curtin University of Technology, Perth, WA, Australia.
Pal
Sebely
S
Thomson
Andrew M
AM
Helmerhorst
Erik
E
Mamo
John C L
JC
D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D002914:Chylomicrons / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D050356:Lipid Metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D013261:Sterols / Q000378:metabolism; D013997:Time Factors
D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D002788:Cholesterol Esters; D002914:Chylomicrons; D007328:Insulin; D008079:Lipoproteins, VLDL; D013261:Sterols; D002784:Cholesterol; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C