CHOLESTEROL BIOSYNTHESIS: THE STARVATION BLOCK

Abstract

Partial localization of the metabolic block in cholesterol biosynthesis from acetate by starved rat liver homogenates has been achieved. Experimental evidence indicates that this block is located in the biosyhthetic pathway between [beta]-hydroxy-[beta]-methyl glutaric acid and squalene. Fractionation and comparative chromatographic examination of incubated homogenates from starved and normal rats failed to reveal any accumulation of an appreciably radioactive intermediate as a result of the blocked biosynthetic pathway in the starved animal. A strongly labelled acidic compound has been isolated in minute amounts from incubated homogenates of both starved and normal rats. This is readily incorporated into cholesterol by liver homogenates from normal, but not from starved rats. Its identity has as yet not been established.