title: Identification of 5 alpha-stanols in patients with sitosterolemia and xanthomatosis: stereochemistry of the protonolysis of steroidal organoboranes.
abstract: Plasma and fecal sterols of patients who exhibited tendon xanthomas with normal plasma cholesterol levels were studied. Plasma levels were (mg/dl mean +/- SD): cholesterol 232 +/- 36; cholestanol 5.9 +/- 2.1 (normal less than 0.6); sitosterol 18 +/- 5.6 (normal less than 1.0); campesterol 11 +/- 3.3 (normal less than 1.0). Other sterols such as sitostanol and campestanol (the 5 alpha-dihydro derivatives of sitosterol and campesterol) were also present in large amounts. Examination of the feces from these subjects showed cholesterol, sitosterol, campesterol and their 5 beta-saturated derivatives. Presence of 5 alpha-stanols in the plasma, and their absence in the feces indicates that the 5 alpha-stanols are synthesized endogenously within the body rather than in the intestine by colonic bacteria. The absolute identification of the structures of these 5 alpha-stanols was elucidated via hydroboration of their corresponding unsaturated sterols coupled with protonolysis of the resultant organoboranes.
mesh_terms: D001880:Boranes; D002776:Cholestanes / Q000097:blood*; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D005243:Feces / Q000032:analysis; D006801:Humans; D006868:Hydrolysis; D013058:Mass Spectrometry; D011522:Protons; D012855:Sitosterols / Q000097:blood*; D013237:Stereoisomerism; D014973:Xanthomatosis / Q000097:blood*
chemical_list: D001880:Boranes; D002776:Cholestanes; D011522:Protons; D012855:Sitosterols