Adipose tissue lipid metabolism

Another family of nuclear hormone receptors intimately involved in adipose tissue lipid metabolism is the liver X receptors (LXR), which also heterodimerize with RXRa. Within... 

The present study demonstrated that CLA accumulates in the liver lipids of rats (Tables 4 and 5) and liver or adipose tissue lipids of mice (Tables 6 and 7) fed CLN diets. The CLA detected in these tissue lipids was identified as c9,fll-CLA for PGO and BGO diets, the t9,rl 1-CLA isomer for the CTO diet, and f8,fl0-CLA for the PMO diet. The main CLN isomers contained in the PGO, BGO, CTO, and PMO diets were c9,tll,cl3-CLN, c9,tlI,rl3-CLN, t9,tll,cl3-CLN, and t8,tlO,cl2-CLN, respectively. Therefore, the formation of the CLA isomer in the tissue lipids of the animals fed the CLN diets may be explained by the enzymatic conversion of CLN to CLA, namely, the biohydrogenation at carbon 13 or carbon 12 double bonds. This metabolic pathway was confirmed by the result that no CLN was detected in the... 

Effect of Insulin and Diabetes on Adipose Tissue. For a long time, the role of adipose tissue in metabolism was underestimated. It is now clear that the adipose tissue cell is more than a site of lipid storage. It is also an actively metabolizing cell—performing lipid synthesis and breakdown—with well-developed... 

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,... 

Insulin resistance occurs when the normal response to a given amount of insulin is reduced. Resistance of liver to the effects of insulin results in inadequate suppression of hepatic glucose production insulin resistance of skeletal muscle reduces the amount of glucose taken out of the circulation into skeletal muscle for storage and insulin resistance of adipose tissue results in impaired suppression of lipolysis and increased levels of free fatty acids. Therefore, insulin resistance is associated with a cluster of metabolic abnormalities including elevated blood glucose levels, abnormal blood lipid profile (dyslipidemia), hypertension, and increased expression of inflammatory markers (inflammation). Insulin resistance and this cluster of metabolic abnormalities is strongly associated with obesity, predominantly abdominal (visceral) obesity, and physical inactivity and increased risk for type 2 diabetes, cardiovascular and renal disease, as well as some forms of cancer. In addition to obesity, other situations in which insulin resistance occurs includes... 

Vernon, R.G. (1981). Eipid metabolism in the rumen. In Lipid Metabolism in the Adipose Tissue of Ruminant Animals, ed. Christie, W.W., Pergamon, Oxford, pp. 279-362. 

In adipose tissue, insulin stimulation suppresses triglyceride hydrolysis (to free fatty acids and glycerol) by activating cAMP phosphodiesterase (cAMP PDE). Cyclic AMP, (3, 5 cAMP), is required to stimulate hormone sensitive lipase (HSL), the enzyme which hydrolyses triglyceride within adipocytes PDE converts active 3, 5 cAMP to inactive 5 AMP thus preventing the stimulation of HSL. The net effect of insulin on lipid metabolism is to promote storage. 

TBBPA concentrations in human plasma in the low ng/g lipids range have been reported (Table 2). Concentrations and detection frequency of TBBPA in adipose tissue are even lower due to the relatively low lipophilic properties of TBBPA ( ow = 5), and the metabolic fate of this BFR. 

The lipid metabolism of adipose tissue is also influenced by the hormone. In these cells, insulin stimulates the reorganization of glucose into fatty acids. This is mainly based on activation of acetyl CoA carboxylase (see p. 162) and increased availability of NADPH+H due to increased PPP activity (see p. 152). On the other hand, insulin also inhibits the degradation of fat by hormone-... 

Lipid metabolism in the liver is closely linked to the carbohydrate and amino acid metabolism. When there is a good supply of nutrients in the resorptive (wellfed) state (see p. 308), the liver converts glucose via acetyl CoA into fatty acids. The liver can also take up fatty acids from chylomicrons, which are supplied by the intestine, or from fatty acid-albumin complexes (see p. 162). Fatty acids from both sources are converted into fats and phospholipids. Together with apoproteins, they are packed into very-low-density lipoproteins (VLDLs see p.278) and then released into the blood by exocytosis. The VLDLs supply extrahepatic tissue, particularly adipose tissue and muscle. 

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. 

The Pj receptor is distinct from the Pj or Pj receptor. In humans, the Pj receptor is linked to obesity, diabetes, and control of lipid metabolism. mRNA for Pj receptors is selectively expressed in brown adipose tissue in newborn humans. Polymorphism is common within the structure of the Pj receptor. A Trp64Arg point mutation in the Pj... 

Effects on lipid metabolism Adipose tissue responds within minutes to administration of insulin, which causes a significant reduc tion in the release of fatty acids ... 

Effects on lipid metabolism Glucagon favors hepatic oxidation of fatty acids and the subsequent formation of ketone bodies fan acetyl CoA. The lipolytic effect of glucagon in adipose tissue is minimal in humans. 

---