Hepatic Lipid Metabolism

The liver is a major regulator of lipid metabolism in the body. It plays a central role in the synthesis and degradation (oxidation) of fatty acids. Fatty acids serve as an important source of energy as well as energy storage for many organisms and are also pivotal for a variety of biological processes, including the synthesis of cellular membrane lipids and generation of lipid-containing messengers involved in signal transduction [1]. Fatty acids can generally be stored efficiently as non-toxic triglycerides (triacylglycerols/fat), which generate more than twice as much energy, for the same mass, as do carbohydrates or proteins. Accordingly, liver is a key player in energy homeostasis: first, as it converts excess dietary glucose into fatty acids that are then exported to other tissues for storage as triglycerides as lipid droplets [2]; second, under conditions of increase in synthesis and decreased oxidation of fatty acids the liver contributes to the progressive accumulation of excess unspent energy in the form of energy-dense triglycerides in adipocytes of adipose tissue, which provide virtually limitless capacity to store energy and finally, under chronic energy over-load situations the liver may serve as a surrogate reservoir for storing considerable quantities of excess fat, leading to the development of hepatic steatosis and steatohepatitis [3].