Adipose tissue metabolism

A Variety of Mechanisms Have Evolved for Fine Control of Adipose Tissue Metabolism... 

Mechanism of Action An antioxidant that prevents oxidation of vitamins A and C, protects fatty acids from aff ack by free radicals, and protects RBCs from hemolysis by oxidizing agents. Therapeutic Effect Prevents and treats vitamin E deficiency. Pharmacokinetics Variably absorbed from the GI tract (requires bile salts, dietary fat, and normal pancreatic function). Primarily concentrated in adipose tissue. Metabolized in the liver. Primarily eliminated by biliary system. 

Major metabolic pathways in adipose tissue in the absorptive state. [Note The numbers in the circles, which appear both on the figure and in the corresponding text, indicate important pathways for adipose tissue metabolism.]... 

Villarroya F, Giralt M, and Iglesias R (1999) Retinoids and adipose tissues metabolism, cell differentiation and gene expression. International Journal of Obesity and Related Metabolic Disorders 23,1-6. 

Amer, P (1995). Techniques for the measurement of white adipose tissue metabolism A practical guide. Int. j. Obesity 19,435-442. 

Methoxyethanol is rapidly absorbed through the skin and lungs into the blood. Its water solubility favors distribution to all body tissues except adipose tissue. Metabolism occurs via two pathways. Methoxyethanol is a substrate for alcohol dehydrogenase, and the resultant methoxyacetaldehyde is metabolized to methoxyacetic acid by aldehyde dehydrogenase. In rats, pretreatment with phenobarbitol decreased formation of methoxyacetaldehyde but accelerated formation of methoxyacetate in liver cytosolic fractions. A minor pathway involves demethylation by undefined enzymes to ethylene glycol and CO2. 

Murray, A.D. Sniderman, and K. Cianflone, Acylation stimulating protein (ASP) deficiency alters postprandial and adipose tissue metabolism in male mice, J. Biol. Chem., 1999, 274, 36219-36225. 

Collins S, Surwit RS. The beta-adrenergic receptors and the control of adipose tissue metabolism and thermogenesis. Rec Prog Horm Res 2001 56 309-328. 

See also Brain Metabolism, Muscle Metabolism, Heart Metabolism, Adipose Tissue Metabolism, Blood Metabolism, Hormonal Regulation of Fuel Metabolism... 

It is important to know that because of the drugs effects on adipose tissue metabolism and the distribution of adipose stores in the body, several weeks to months are typically required to observe a clinical response. It is helpful to instruct patients that there is an expected delay in the glucose lowering effects on a thiazolidinedione, so they can anticipate the clinical outcome. In addition, patients should be followed on a starting dose for 3 months, before increasing the dose. 

HagstrOm-Toft, E., Amer, P., Johansson, U., Eriksson, L. S., Ungerstedt, U., and Bolinder, J. (1992). Effect of insulin on human adipose tissue metabolism in situ. Interactions with beta-adrenoceptors. Diabetologia 35,664. 

D, P, Katz and J. L. Knillle. The effect of medium and long chain triglyceride on human adipose tissue metabolism. Lipids. 22 4,35-441. 1987. 

To provide a background for the hormonal effects to be discussed, a brief account of the pertinent aspects of adipose tissue metabolism is presented. Wertheimer and Shapiro (1948 Shapiro and Wertheimer, 1956), Wertheimer and Shafrir (I960), and Jeanrenaud (1961) have reviewed this subject in some detail. 

---