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Apolipoprotein B metabolism and the distribution of VLDL and LDL subfractions.
J Lipid Res. 2000 Feb; 41(2):305-18.JL

Abstract

Apolipoprotein B (apoB) metabolism was investigated in 20 men with plasma triglyceride 0.66-2.40 mmol/l and plasma cholesterol 3.95-6. 95 mmol/l. Kinetics of VLDL(1) (S(f) 60-400), VLDL(2) (S(f) 20-60), IDL (S(f) 12-20), and LDL (S(f) 0;-12) apoB were analyzed using a trideuterated leucine tracer and a multicompartmental model which allowed input into each fraction. VLDL(1) apoB production varied widely (from 5.4 to 26.6 mg/kg/d) as did VLDL(2) apoB production (from 0.18 to 8.4 mg/kg/d) but the two were not correlated. IDL plus LDL apoB direct production accounted for up to half of total apoB production and was inversely related to plasma triglyceride (r = -0.54, P = 0.009). Percent of direct apoB production into the IDL/LDL density range (r = 0.50, P < 0.02) was positively related to the LDL apoB fractional catabolic rate (FCR). Plasma triglyceride in these subjects was determined principally by VLDL(1) and VLDL(2) apoB fractional transfer rates (FTR), i.e., lipolysis. IDL apoB concentration was regulated mainly by the IDL to LDL FTR (r = -0.71, P < 0.0001). LDL apoB concentration correlated with VLDL(2) apoB production (r = 0.48, P = 0.018) and the LDL FCR (r = -0.77, P < 0. 001) but not with VLDL(1), IDL, or LDL apoB production. Subjects with predominantly small, dense LDL (pattern B) had lower VLDL(1) and VLDL(2) apoB FTRs, higher VLDL(2) apoB production, and a lower LDL apoB FCR than those with large LDL (pattern A). Thus, the metabolic conditions that favored appearance of small, dense LDL were diminished lipolysis of VLDL, resulting in a raised plasma triglyceride above the putative threshold of 1.5 mmol/l, and a prolonged residence time for LDL. This latter condition presumably permitted sufficient time for the processes of lipid exchange and lipolysis to generate small LDL particles.

Authors+Show Affiliations

Institute of Biochemistry, Glasgow Royal Infirmary University NHS Trust, Castle Street, Glasgow G4 OSF, UK.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10681415

Citation

Packard, C J., et al. "Apolipoprotein B Metabolism and the Distribution of VLDL and LDL Subfractions." Journal of Lipid Research, vol. 41, no. 2, 2000, pp. 305-18.
Packard CJ, Demant T, Stewart JP, et al. Apolipoprotein B metabolism and the distribution of VLDL and LDL subfractions. J Lipid Res. 2000;41(2):305-18.
Packard, C. J., Demant, T., Stewart, J. P., Bedford, D., Caslake, M. J., Schwertfeger, G., Bedynek, A., Shepherd, J., & Seidel, D. (2000). Apolipoprotein B metabolism and the distribution of VLDL and LDL subfractions. Journal of Lipid Research, 41(2), 305-18.
Packard CJ, et al. Apolipoprotein B Metabolism and the Distribution of VLDL and LDL Subfractions. J Lipid Res. 2000;41(2):305-18. PubMed PMID: 10681415.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Apolipoprotein B metabolism and the distribution of VLDL and LDL subfractions. AU - Packard,C J, AU - Demant,T, AU - Stewart,J P, AU - Bedford,D, AU - Caslake,M J, AU - Schwertfeger,G, AU - Bedynek,A, AU - Shepherd,J, AU - Seidel,D, PY - 2000/2/19/pubmed PY - 2000/4/29/medline PY - 2000/2/19/entrez SP - 305 EP - 18 JF - Journal of lipid research JO - J. Lipid Res. VL - 41 IS - 2 N2 - Apolipoprotein B (apoB) metabolism was investigated in 20 men with plasma triglyceride 0.66-2.40 mmol/l and plasma cholesterol 3.95-6. 95 mmol/l. Kinetics of VLDL(1) (S(f) 60-400), VLDL(2) (S(f) 20-60), IDL (S(f) 12-20), and LDL (S(f) 0;-12) apoB were analyzed using a trideuterated leucine tracer and a multicompartmental model which allowed input into each fraction. VLDL(1) apoB production varied widely (from 5.4 to 26.6 mg/kg/d) as did VLDL(2) apoB production (from 0.18 to 8.4 mg/kg/d) but the two were not correlated. IDL plus LDL apoB direct production accounted for up to half of total apoB production and was inversely related to plasma triglyceride (r = -0.54, P = 0.009). Percent of direct apoB production into the IDL/LDL density range (r = 0.50, P < 0.02) was positively related to the LDL apoB fractional catabolic rate (FCR). Plasma triglyceride in these subjects was determined principally by VLDL(1) and VLDL(2) apoB fractional transfer rates (FTR), i.e., lipolysis. IDL apoB concentration was regulated mainly by the IDL to LDL FTR (r = -0.71, P < 0.0001). LDL apoB concentration correlated with VLDL(2) apoB production (r = 0.48, P = 0.018) and the LDL FCR (r = -0.77, P < 0. 001) but not with VLDL(1), IDL, or LDL apoB production. Subjects with predominantly small, dense LDL (pattern B) had lower VLDL(1) and VLDL(2) apoB FTRs, higher VLDL(2) apoB production, and a lower LDL apoB FCR than those with large LDL (pattern A). Thus, the metabolic conditions that favored appearance of small, dense LDL were diminished lipolysis of VLDL, resulting in a raised plasma triglyceride above the putative threshold of 1.5 mmol/l, and a prolonged residence time for LDL. This latter condition presumably permitted sufficient time for the processes of lipid exchange and lipolysis to generate small LDL particles. SN - 0022-2275 UR - https://www.unboundmedicine.com/medline/citation/10681415/Apolipoprotein_B_metabolism_and_the_distribution_of_VLDL_and_LDL_subfractions_ L2 - http://www.jlr.org/cgi/pmidlookup?view=long&amp;pmid=10681415 DB - PRIME DP - Unbound Medicine ER -