Kamis, 13 Desember 2012

cholesterol


cholesterol

Cholesterol is a chemical compound that is naturally produced by the body. Cholesterol is a combination of lipid (fat) and sterol (a combination steroid and alcohol) (Wedro et al., 2010; Zamora A., 2007). Cholesterol is an essential structural component of the cell membrane and the myelin sheath (A. Zamora, 2007).
Approximately 80% of cholesterol is produced in the liver, the rest is obtained from food (diet). Dietary cholesterol comes mainly from meat, poultry, and fish. Internal organs such as the liver generally contain high amounts of cholesterol (Wedro et al., 2010).



Figure 1. The molecular structure of cholesterol
(Source: A. Zamora, 2007)
 
Cholesterol plays a role in many metabolic processes, synthesis of hormones such as estrogen, testosterone and adrenaline, the production of vitamin D, and bile acids that help the body digest fats and absorb fat-soluble vitamins in the gastrointestinal tract (P. Lavelle, 2006; Zamora A., 2007; Wedro et al., 2010), and insulate axons in nerve cells (A. Zamora, 2007).





cholesterol biosynthesis pathway

Figure 2. Cholesterol synthesis in the body.
(Source: A.P. et al., 1997)


Enzymes are important in the synthesis of cholesterol is HMG CoA reductase.