Nutritional regulation of lipoprotein lipase.

Lipoprotein lipase (LPL) is needed for normal catabolism of triglyceride-rich lipoproteins. In some tissues, notably the adipose tissue, the local LPL activity is an important determinant for how much lipid is taken up. There is regulation of gene expression, but the rapid changes that occur in response to the nutritional state are mediated mainly by post-transcriptional mechanisms. In the fed state, the adipose tissue expresses its full potential for LPL production, as set by the mRNA levels and the rate of protein synthesis. During fasting, LPL activity is suppressed by an unknown post-translational mechanism. In heart, regulation is primarily exerted on the equilibrium between LPL at endothelial sites and LPL in blood, with more endothelial LPL in the fasted state. LPL forms complexes with fatty acids which results in shut-down of lipolysis and detachment of both lipase and lipoproteins from the endothelial site. This provides a molecular coupling device between the cellular metabolic state and the rate of lipoprotein catabolism. There is growing evidence that LPL is a ligand for binding of lipoprotein particles such as chylomicron remnants to cell surfaces and receptors.