Journal of Lipid Research (Jul 1976)
Bile acids. LI. Formation of 12α-hydroxyl derivatives and companions from 5α-sterols by rabbit liver microsomes
Abstract
A comparison of the activity of rabbit liver microsomes fortified with 0.1 mM NADPH to promote 12α-hydroxylation over 60 minutes with appropriate sterols provided the following relative order of activities: 5α-cholestane-3α, 7α-diol, 100; 7α-hydroxy-5α-cholestane-3-one, 76; 7α-hydroxycholest-4-en-3-one, 64; 5α-cholestane-3-3β, 7α-diol, 24; allochenodeoxycholate, 22. If the more polar products are included, the first three sterols are equivalent in product formation. Investigation by gas-liquid chromatography-mass spectrometry of the nature of these more polar products derived from 5α-cholestane-3α, 7α-diol showed that a series of tetrols was formed; i.e., 5α-cholestane-3α, 7α, 12α, 25-tetrol as the major product and lesser amounts of 5α-cholestane-3α, 7α, 12α, 24- and 3α, 7α, 12α, 23-tetrols. No significant amount of 26-hydroxylated product was formed.
