Fat mobilization

Picard, F., Kurtev, M., Chung, N., Topark-Ngarm, A., Senawong, T, Machado De Oliveira, R., Leid, M McBurney, M.W. and Guarente, L. (2004) Sirtl promotes fat mobilization in white adipocytes by repressing PPAR-gamma. Nature, 429, 771-776. 

Dysfunction of fat metabolism is caused by the low insulin/glucagon ratio, which stimulates fat mobilization by adipose tissue, flooding the liver with fatty acids and raising intracellular acetyl CoA levels. 

Mechanism of Action A polypeptide hormone that stimulates cartilaginous growth areas of long bones, increases the number and size of skeletal muscle cells, influences the size of organs, and increases RBC mass by stimulating erythropoietin. Influences the metabolism of carbohydrates (decreases insulin sensitivity), fats (mobilizes fatty acids), minerals (retains phosphorus, sodium, potassium by promotion of cell growth), and proteins (increases protein synthesis). Therapeutic Effect Stimulates growth. 

This paper is one of a series that reviews the factors that influence fat mobilization and utilization during exercise. 

New section on the role of perilipin phosphorylation in the control of fat mobilization New discussion of the role of acetyl-CoA in the integration of fatty acid oxidation and synthesis... 

K.N. Frayn, S.W. Coppack, B.A. Fielding, and S.M. Humphreys, Coordinated regulation of hormone-sensitive lipase and lipoprotein lipase in human adipose tissue in vivo implications for the control of fat storage and fat mobilization, Adv. Enzyme Regul., 1995, 35, 163—178. 

See also Adipocytes, Fat Absorption and Transport, Bile Salts and Emulsion of Fats, Mobilization of Stored Fat, Energy Storage, Triacylglycerol Synthesis, Action of Insulin, Lipids... 

Regulation, Glycogen Breakdown, Kinase Cascade in Fat Mobilization (from Chapter 18), Second Messenger Systems... 

By fatty acid substrate availability by hormonal control of fat mobilization... 

TAGs serve as food stores and are therefore the most abmidant lipid in animals. They exist in most cell types but are especially prevalent in adipose tissue when they are known as depot fat. The hydrolysis of the ester bonds of TAGs and the release of glycerol and fatty acids from adipose tissue is referred to as fat mobilization. Depot fat is a water-free mixture of TAGs that differ from each other in the nature of the three fatty acyl groups which they contain. 

Other conditions where increased fat mobilization has been implicated in fatty liver are fasting (Dole, 1956), diabetic acidosis (Bierman et al., 1957), thyrotoxicosis (Rich et dl., 1958), excessive growth hormone (Raben and Hollenberg, 1959), or catecholamine production (Feigelson et al., 1961). 

Important reviews on this subject have already appeared (Vaughan, 1961 Jeamenaud, 1961 Rudman, 1963 Havel, 1964). Recent evidence for a possible correlation between fat mobilization and lipoprotein metabolism will be briefly discussed. 

Eaton (1963) has postulated an association between the known hy-polipoproteinemic effect of nicotinic acid (Altschul et al., 1955 Parson et al., 1956) and the inhibition by the compound of the fat-mobilizing action of norepinephrine (Eaton, 1963 Carlson and Oro, 1962). Nicotinamide, which has no effect on circulating lipoproteins (Mfller et al., 1962), failed to inhibit FFA mobilization by norepinephrine (Eaton, 1963 Carlson and Oro, 1962). 

Explain what happens during fat mobilization. (Section 14.2)... 

The glycerol available from fat mobilization is first phos-phorylated and then oxidized to dihydroxyacetone phosphate, an intermediate of glycosis. By having an entry point into the glycolysis pathway, glycerol can nltimately be converted into glucose or oxidized to CO2 and H2O. 

Fat mobilization is the process of hydrolyzing triglycerides to produce fatty acids and glycerol, both of which can be used for energy in muscle cells. 

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