VLDL is composed of ~60% triacylglyceride (TAG), and its role is to transport those TAGs to target tissues.
Nascent VLDL is formed in the
where lipid particles are assembled on Apo B-100, then released directly into the bloodstream. Once in the bloodstream, VLDL acquires additional apolipoproteins from circulating HDL, just like chylomicrons. As VLDL circulates, lipoprotein lipase acts on the TAG and releases fatty acids into the target tissue (adipose, for example).
As this process continues, VLDL becomes smaller and desner, triggering the next metabolic step. VLDL interacts with HDL and results in the transfer of all except
to HDL (note that not necessarily all of each component are transferred). Once these modifications are complete, the VLDL can either become an IDL that is endocytosed, or it can be converted into
in the plasma.