Metabolic regulation adipose tissue

McNamara JP Role and regulation of metabolism in adipose tissue during lactation. J Nutr Biochem 1995 6 120. 

JRS Arch, S Wilson. (33-Adrenoceptors and the regulation of metabolism in adipose tissues. Biochem Soc Trans 24 412-418, 1996. 

Insulin is a peptide hormone, secreted by the pancreas, that regulates glucose metabolism in the body. Insufficient production of insulin or failure of insulin to stimulate target sites in liver, muscle, and adipose tissue leads to the serious metabolic disorder known as diabetes mellitus. Diabetes afflicts millions of people worldwide. Diabetic individuals typically exhibit high levels of glucose in the blood, but insulin injection therapy allows diabetic individuals to maintain normal levels of blood glucose. 

Uptake of LCFAs across the lipid-bilayer of most mammalian cells occurs through both a passive diffusion of LCFAs and a protein-mediated LCFA uptake mechanism. At physiological LCFA concentrations (7.5 nM) the protein-mediated, saturable, substrate-specific, and hormonally regulated mechanism of fatty acids accounts for the majority (>90%) of fatty acid uptake by tissues with high LCFA metabolism and storage such as skeletal muscle, adipose tissue, liver,... 

The regulation of fat metabolism is relatively simple. During fasting, the rising glucagon levels inactivate fatty acid synthesis at the level of acetyl-CoA carboxylase and induce the lipolysis of triglycerides in the adipose tissue by stimulation of a hormone-sensitive lipase. This hormone-sensitive lipase is activated by glucagon and epinephrine (via a cAMP mechanism). This releases fatty acids into the blood. These are transported to the various tissues, where they are used. 

Sharma AM, Staels B. Review peroxisome proliferator-activated receptor y and adipose tissue - understanding obesity-related changes in regulation of lipid and glucose metabolism. J Clin Endocrinol Metab 2007 92 386-95. 

Features an important new section on glyceroneogenesis and the triacylglycerol cycle between adipose tissue and liver, including their roles in fatty acid metabolism (especially during starvation) and the emergence of thiazolidinediones as regulators of glyceroneogenesis in the treatment of type II diabetes... 

CM and VLDL secreted by intestinal cells and VLDL synthesized and secreted in the liver have similar metabolic fates. After secretion into the blood, newly formed CM and VLDL take up apoprotein (apo-C) from HDL and are subsequently removed from the blood (plasma half-life of less than 1 h in humans [137]) primarily by the action of lipoprotein lipase (LPL). Lipoprotein lipase is situated mainly in the vascular bed of the heart, skeletal muscle, and adipose tissue and catalyzes the breakdown of core TG to monoglycerides and free fatty acids, which are taken up into adjacent cells or recirculated in blood bound to albumin. The activity of LPL in the heart and skeletal muscle is inversely correlated with its activity in adipose tissue and is regulated by various hormones. Thus, in the fasted state, TG in CM and VLDL is preferentially delivered to the heart and skeletal muscle under the influence of adrenaline and glucagon, whereas in the fed state, insulin enhances LPL activity in adipose tissue, resulting in preferential uptake of TG into adipose tissue for storage as fat. 

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