There are two major pathways that mammalian cells use to supply themselves with
cholesterol, one involving the synthesis of sterols from acetyl-CoA and the other the
metabolism of cholesterol-rich lipoprotein particles via receptor-mediated endocytosis.
There also are several pathways that mammalian cells use to break down cholesterol, and
these disposal pathways are equal in physiological importance to the supply pathways. A
major catabolic route involves conversion of cholesterol into conjugated bile salts, a …