Plasma methyl sterol sulfates in familial hypercholesterolemia after partial ileal bypass.

We demonstrate, in this study, the presence of several unidentified components in the sterol sulfate fraction of familial hypercholesterolemia patients treated with partial ileal bypass surgery. The sterols obtained after solvolysis and derivatization of this fraction had a retention time, on gas-liquid chromatography, intermediate between cholesterol and beta-sitosterol. They were not present in the sterol sulfate fraction obtained from normal subjects, hypercholesterolemic patients, or ileal bypass subjects before surgery or after reanastomosis. The substances isolated from the sterol sulfate fraction were identified by combined gas-liquid chromatography and mass spectrometry to be 24,25-dihydrolanosterol, 4,4-dimethyl-5alpha-cholest-8-en-3beta-ol, 4,4-dimethyl-5alpha-cholest-9(11)-en-3beta-ol, 4alpha-methyl-5alpha-cholest-7-en-3beta-ol, and 4alpha-methyl-5alpha-cholest-8-en-3beta-ol. Their free forms are known to be biosynthetic intermediates in the transformation of lanosterol into cholesterol.