Because most serum triacylglycerol is transported by VLDL,
hepatic production or rate of secretion of VLDL triacylglycerol and
hydrolysis or removal of circulating triacylglycerol are 2 key determinants
of serum triacylglycerol concentrations. The underlying
mechanism for the hypotriacylglycerolemic effect of MUFAs is not
clear. However, McNamara (29) proposed 2 complementary mechanisms
that may be involved: 1) changes in the composition of
VLDL and 2) changes in the expressed activities of the enzymes
and proteins involved in intravascular processing and catabolism of
VLDL, both of which would decrease plasma triacylglycerol concentrations.
The fatty acid composition of VLDL triacylglycerol,
which is affected by dietary fatty acid composition, is a determinant determinant
for the conversion of VLDL into other lipoproteins and the
metabolism of triacylglycerols (30). Therefore, the rates of VLDL
production and clearance of triacylglycerol may be altered as a
result of the amount and type of fat in the diet (31, 32).