Regulation metabolic sensitivities

PPARa is predominantly expressed in cataboHcally active tissues such as liver, heart, kidney, and muscle. It is involved in the uptake and oxidation of fatty acids as well as in lipoprotein metabolism. PPARy is mainly expressed in adipose tissue and regulates insulin sensitivity, glucose and fatty add utilization as well as adipocyte differentiation (Hao Zhang et al. 2009). Recent studies have foimd that PPARS is also a regulator of serum lipids... 

Swanton, C., Marani, M., Pardo, O. et al. 2007. Regulators of mitotic arrest and ceramide metabolism are determinants of sensitivity to paclitaxel and other chemotherapeutic drugs. Cancer Cell, 11 (6) 498—512. 

Chemoreceptors provide the most important input to the medullary respiratory center in terms of regulating ventilation to meet the metabolic requirements of the body. Chemoreceptors are sensitive to changes in P02, PC02, and pH. The two types of chemoreceptors are ... 

Similarly, the regulation of PDK activity is modified in adult muscle PDC. For example, PDK activity is inhibited by pyruvate and propionate (metabolites elevated during anaerobic metabolism) and is less sensitive to stimulation by elevated NADH/NAD+ and acetyl CoA/CoA ratios (Fig. 14.2) (Thissen et al, 1986 Chen et al, 1998). The effects of NADH and acetyl CoA on PDK activity are mediated by the degree of E3-catalysed oxidation and E2-catalysed acetylation of the inner lipoyl domain of E2 (Roche and Cate, 1977 Rahmatullah and Roche, 1985, 1987 Ravindran et al, 1996 Yang et al, 1998), so that the regulation of this phenomenon is complex and involves multiple interacting components. 

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. 

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