In vitro effects of oxygenated lanosterol derivatives on cholesterol biosynthesis from 24,25-dihydrolanosterol.

Abstract
The effects of oxygenated lanosterol derivatives (1-27, 5 .mu.M) including 32-oxygenated lanosterol derivatives on cholesterol biosynthesis from [24,25-3H2]-24,25-dihydrolanosterol (18 .mu.M) were tested in 10,000 .times. g supernatant (S-10) fraction of rat liver homogenate. Among the derivatives, 7-oxolanost-8-en-3.beta.-ol (7-oxo-DHL), 3.beta.-acetoxylanost-8-en-7-one (7-oxo-DHL-3-OAc), and 7-oxolanosta-5,8,11-trien-3.beta.-ol were highly active in depressing cholesterol biosynthesis from 24,25-dihydrolanosterol. The inhibitory activities of these derivatives on cholesterol synthesis are discussed on the basis of the position and stereochemistry of the oxygen functional groups on the sterol nucleus. The effect of aphidicolin on cholesterol synthesis was also compared with that of 7-oxo-DHL.