Cholesterol oxidation and 7 alpha-hydroxylation during postnatal development of the rat.

The activity of rat hepatic cholesterol 7 alpha-hydroxylase is low in the suckling period and rises at weaning. The oxidation of intraperitoneally administered 26(-14)C-cholesterol to 14CO2 is also low in suckling rats and increases with age as does the radioactivity in the plasma. In contrast, propionic acid oxidation to CO2 is much more rapid, suggesting that the side chain cleavage of cholesterol is not a rate-limiting process.