Synthesis and function of hepatic very-low-density lipoprotein.
Most of the triacylglycerol (TAG) utilized for the assembly of very-low-density lipoprotein (VLDL) in the secretory apparatus of the hepatocyte is mobilized by lipolysis of the cytosolic TAG pool, followed by re-esterification. The lipases involved include arylacetamide deacetylase and/or triacylglycerol hydrolase. Some of the re-esterified products of lipolysis gain access to an apolipoprotein-B-rich VLDL precursor to form mature VLDL. Some, however, are returned to the cytosolic pool in a process that is stimulated by insulin and inhibited by microsomal triacylglycerol transfer protein (MTP). Phospholipids also contribute to VLDL TAG in a process which involves ADP-ribosylation factor-1 (ARF-1)-mediated activation of phospholipase D. The temporary storage of TAG in the liver, followed by its mobilization and secretion as VLDL, form part of a process by which the liver protects vulnerable body tissues from excess lipotoxic non-esterified ('free') fatty acids in the plasma.
Gibbons
G F
GF
Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK. geoff.gibbons@mrl.ox.ac.uk
Wiggins
D
D
Brown
A-M
AM
Hebbachi
A-M
AM
D000818:Animals; D001055:Apolipoproteins B / Q000378:metabolism; D006801:Humans; D008079:Lipoproteins, VLDL / Q000096:biosynthesis* / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D010316:Particle Size; D014280:Triglycerides / Q000378:metabolism
D001055:Apolipoproteins B; D008079:Lipoproteins, VLDL; D014280:Triglycerides