Free fatty acids sources

Triacylglycerol is the main storage Hpid in adipose tissue. Upon mobihzation, free fatty acids and glycerol are released. Free fatty acids are an important fuel source. 

Glucose derived from muscle glycogen and metabolized by anaerobic glycolysis is the major fuel source. Blood glucose and free fatty acids are the major fuel sources. 

Cortisol-induced lipolysis not only provides substrates for gluconeogenesis (formation of glucose from noncarbohydrate sources) but it also increases the amount of free fatty acids in the blood. As a result, the fatty acids are used by muscle as a source of energy and glucose is spared for the brain to use to form energy. 

Lipids can be oxidized by some ROS such as hydroxyl ( OH). but not by H202, NO, or 02 - (Halliwell and Gutteridge 1999). However, both enzymatic and nonenzymatic cellular mechanisms can oxidize fatty acids. Challenging L. digitata sporophytes with lipopolysaccharides from various sources resulted in a rapid release of free fatty acids (FFAs) with a concomitant accumulation of oxidized derivatives of linolenic (08 2) and eicosapentaenoic acid (C20 5) (Kiipper et al. 2006). Other strong inducers of the oxidative burst, such as oligoguluronates, in Laminaria could induce neither the release of FFAs nor the oxylipin production. These results... 

Nicotinic acid decreases formation and secretion of VLDL by the liver (mechanism III in Fig. 23.2). This action appears secondary to its ability to inhibit fatty acid mobilization from adipose tissue. Circulating free fatty acids provide the main source of fatty acids for hepatic... 

The major source of free fatty acids in the blood is from the breakdown of triacylglycerol stores in adipose tissue which is regulated by the action of hormone-sensitive triacylglycerol lipase (see Topic K4). Fatty acid breakdown and fatty acid synthesis are coordinately controlled so as to prevent a futile cycle (see Topic K3). 

Woo, A.H., Lindsay, R.C. 1983b. Stepwise discriminant analysis of free fatty acid profiles for identifying sources of lipolytic enzymes in rancid butter. J. Dairy Sci. 66, 2070-2075. 

Insulin is probably the most important inhibitor of lipolysis. In contrast to adults, in whom catecholamines represent the most important stimulators of lipolysis, thyrotropin (TSH) is the most important stimulator of lipolysis in the newborn. Plasma free fatty acid concentrations rise markedly in the first hours after birth in response to a marked increase in the TSH concentration and a fall in the insulin concentration. The fatty acids released from lipid stores are oxidized by some extrahepatic tissues (e.g., heart and skeletal muscle, kidney, intestine, and lung). Because the respiratory quotient (the ratio of carbon dioxide production to oxygen use) falls from a value of 1.0 (showing that carbohydrate oxidation is the primary source of energy) to a value of 0.8 to 0.9 (showing increasing oxidation of protein or fatty acids) at 2 to 12 hours of age, at a time when protein catabolism is usually insignificant, fatty acid oxidation must represent... 

Can free fatty acids serve as a direct source of glucose (i.e., can fatty acids be converted into glucose) Why or why not ... 

Lecithin, both natural and refined grades, occurs as a substance varying in consistency from plastic to fluid depending on free fatty acid and oil content and on the presence or absence of other diluents. Its color varies from light yellow to brown, depending on the source, on crop variations, and on whether it is bleached or unbleached. Lecithin is obtained from soybeans and other plant sources. 

This procedure is used to determine the lipase activity in preparations derived from microbial sources. The assay is based on the measurement of the amount of free fatty acids formed from an olive oil emulsion in the presence of sodium taurocholate over a fixed time interval. This assay is particularly used for measuring lipase activity in foods. 

Naturally occurring oils and fats constitute another important source of renewable raw materials [198]. Whether they are referred to as fats or oils depends on whether they are solid or liquid at room temperature, respectively. They are composed primarily of triglycerides (triesters of glycerol) together with small amounts of free fatty acids, phospholipids, sterols, terpenes, waxes and vitamins. Oils and fats are either of vegetable or animal origin and are produced in the approximate proportions 55% vegetable oils, 40% land-animal fats and 5% marine oils [199]. 

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