title: The presence of 5 alpha-sitostanol in the serum of a patient with phytosterolemia, and its biosynthesis from plant steroids in rats with bile fistula.
abstract: The presence of 5 alpha-sitostanol (24-ethyl-5 alpha-cholestan-3 beta-ol) in serum of a patient with the rare genetic disease phytosterolemia was confirmed. This study aimed at clarifying the pathway(s) for the formation of 5 alpha-sitostanol, by use of rats with bile fistula. 5 alpha-Sitostanol was formed only slowly from sitosterol, but readily from 24-ethyl-4-cholesten-3-one. Some conversion was also obtained with 7 alpha-hydroxysitosterol as precursor. In view of the low rate of 7 alpha-hydroxylation of sitosterol, however, a pathway from sitosterol to 5 alpha-sitostanol involving 7 alpha-hydroxysitosterol as intermediate is probably of small physiological importance. Intestinal microorganisms are not essential for the above conversions, since the 5 alpha-sitostanol was found in bile from bile fistula rats. 5 alpha-Sitostanol was converted to water soluble metabolites (bile acids) much more slowly than was cholestanol (5 alpha-cholestan-3 beta-ol), and was accumulated serum to a much larger extent.
mesh_terms: D000293:Adolescent; D000818:Animals; D001646:Bile / Q000378:metabolism; D001658:Biliary Fistula / Q000378:metabolism*; D002250:Carbon Radioisotopes; D005260:Female; D006801:Humans; D007700:Kinetics; D008052:Lipid Metabolism, Inborn Errors / Q000097:blood*; D008099:Liver / Q000378:metabolism; D013058:Mass Spectrometry; D010944:Plants; D051381:Rats; D011919:Rats, Inbred Strains; D012855:Sitosterols / Q000096:biosynthesis / Q000097:blood*; D013256:Steroids / Q000378:metabolism; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D012855:Sitosterols; D013256:Steroids; D014316:Tritium; C021255:stigmastanol