Cholesterol is a lipid subtype and the focus of this educational activity. While cholesterol is discussed often in the healthcare setting, it may have functions that are less apparent.
Cholesterol:
- promotes fat absorption in the intestine
- is a precursor of steroid hormones such as estrogen and testosterone
- transforms vitamin D in the skin
- is a component of the cellular membrane
Cholesterol can be exogenous or endogenous. About 80% of cholesterol is endogenous, with about 20% being exogenous.
- Endogenous cholesterol (80%) is produced primarily by one's own liver.
- Exogenous cholesterol (20%) is absorbed from animal products in our diet.
Endogenous synthesis of cholesterol is dependent on the enzyme
HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-coenzyme A reductase). This enzyme will become important in the discussion of lipid-lowering medications.
