Long-chain n-3 polyunsaturated fatty acids and serum triacylglycerols
Long chain n-3 PUFAs have potent effects in the liver, where they suppress the production of endogenous TAG by inhibiting the enzymes phosphatidic acid phosphatase and diacylglycerol acyltransferase. They may also selectively increase the degradation of apoB-100, further reducing the production of TAG-rich VLDLs. (Note that apoB-100 is produced constitu-tively, so that the production of VLDL is driven by the supply of substrates for the synthesis of TAG). In addition, long-chain n-3 PUFAs accelerate the clear-ance of TAG-rich lipoproteins from the circulation in the postprandial phase by stimulating the activity of LPL. Together, these effects are thought to underlie the ability of these fatty acids to correct the lipopro-tein abnormalities associated with an ALP. It is also possible that many of the effects of eicosapentaenoic acid/docosahexaenoic acid on blood lipids and other cardiovascular risk factors are mediated through an increase in the sensitivity of tissues to the action of insulin. However, there is, as yet, no convincing evi-dence to support such an effect in adipose tissue, liver, or skeletal muscle.