Effects of hypoxia on sterol synthesis, acyl-CoA:cholesterol acyltransferase activity, and efflux of cholesterol in cultured rabbit skin fibroblasts.

To elucidate the mechanisms of cholesterol accumulation in cells under hypoxic conditions, we tested the effects of hypoxia on sterol synthesis, on the activity of acyl-CoA:cholesterol acyltransferase (ACAT), and on the efflux of cholesterol in cultured rabbit skin fibroblasts. Sterol synthesis was measured by the incorporation of 14C-acetate into sterol, and ACAT activity, by the incorporation of 14C-oleate into cholesteryl ester. Hypoxia suppressed both sterol synthesis and the efflux of cholesterol but increased ACAT activity. These results suggest that hypoxia disturbs the balance of cholesterol metabolism in cells and induces intracellular lipid accumulation.