Zheng, ChunyuIkewaki, KatsunoriWalsh, BrianSacks, Frank2022-08-122006-08Zheng, Chunyu, Katsunori Ikewaki, Brian Walsh, Frank Sacks. "Metabolism of ApoB Lipoproteins of Intestinal and Hepatic Origin During Constant Feeding of Small Amounts of Fat." Journal of Lipid Research 47, no. 8 (2006): 1771-1779. DOI: 10.1194/jlr.M500528-JLR2000022-22751539-7262https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37372997We aimed to identify mechanisms by which apolipoprotein B-48 (apoB-48) could have an atherogenic role by simultaneously studying the metabolism of postprandial apoB-48 and apoB-100 lipoproteins. The kinetics of apoB-48 and apoB-100, each in four density subfractions of VLDL and intermediate density lipoprotein (IDL), were studied by stable isotope labeling in a constantly fed state with half-hourly administration of almond oil in five postmenopausal women. A non-steady-state, multicompartmental model was used. Despite a much lower production rate, VLDL and IDL apoB-48 shared a similar secretion pattern with apoB-100: both were directly secreted into all fractions with similar percentage mass distributions. Fractional catabolic rates (FCRs) of apoB-48 and apoB-100 were similar in VLDL and IDL. We identified a fast turnover compartment of light VLDL that had a residence time of <30 min for apoB-48 and apoB-100. Finally, a high secretion rate of apoB-48 was associated with a slow FCR of VLDL and IDL apoB-100. In conclusion, the intestine secretes a spectrum of apoB lipoproteins, similar to what the liver secretes, albeit with a much lower secretion rate. Once in plasma, intestinal and hepatic triglyceride-rich lipoproteins have similar rates of clearance and participate interactively in similar metabolic pathways, with high apoB-48 production inhibiting the clearance of apoB-100.en-USResearch Subject Categories::NATURAL SCIENCES::Biology::Cell and molecular biologyJournal Article2022-08-1210.1194/jlr.M500528-JLR200