Regulation of hepatic apolipoprotein-B-containing lipoprotein secretion

The overall secretion of hepatic lipid as VLDL may be regulated by (i) changing the number of particles secreted as a result of altering apolipoprotein B output and (ii) changing the degree of lipidation of the particles with triacylglycerol so that their diameters vary over a threefold range. Substantial progress has been made in understanding the pathway of triacylglycerol incorporation into VLDL. Less is understood about the processes that commit apolipoprotein B either to secretion or to presecretory degradation, although both regulated translocation and an early lipidation step of the nascent particle with cholesterol or cholesterol ester have been implicated.