Adipose tissue and lipid metabolism

Publisher Summary This chapter describes the lipid metabolism in adipose tissue and focuses on the biochemistry of the adipocyte. Adipocytes make up approximately one half of the cells in adipose tissue, the remainder being blood and endothelial cells, adipose precursor cells of varying degrees of differentiation, and fibroblasts. In humans, small clusters of adipocytes are present that increase in size during gestation. At the adipose tissue beds, fatty acids are liberated from triacylglycerol-rich lipoproteins through the action of lipoprotein lipase, and the released fatty acids are bound by albumin and are the donors of lipid for fatty acid uptake. Acidification of micelles, blood neutrophils, and hepatocytes accompanies fatty acid uptake, consistent with a diffusion mechanism and indicates that protein-mediated transfer is not necessary. While obesity may seem on the surface to simply be the excess consumption of food compared to energy expenditure, it is a complex metabolic disorder centered on adipose lipid metabolism and cellular signaling systems linked to it. However, genomic and proteomic technology platforms now support the analysis of fat cells under a variety of hormonal, metabolic, and genetic backgrounds.