Comparative methods of quantifying fecal neutral sterols in rats and humans after intravenous [14C]-, [3H] or [2H]cholesterol labeling.
Several methods used to estimate the fecal elimination of neutral sterols and of cholesterol having a plasmatic origin (called 'excreted cholesterol') were compared in rats and humans according to the tracer intravenously administered: 14-14C], [1,2-3H]- or octadeuterated cholesterol. In both species, octadeuterated cholesterol had no isotopic effect and the chance occurrence of epicoprostanol in fecal sterols induced an error in the calculation of the fecal excretion of cholesterol. In humans, the use of [1,2-3H]cholesterol appeared to be inaccurate in measuring the fecal flows of cholesterol, because of a loss of 3H radioactivity during the bacterial transformation of cholesterol in the digestive tract. Consequently, the reference method needed to calculate the proportion of excreted cholesterol in fecal cholesterol consisted in dividing the isotopic concentration measured in purified fecal cholesterol by that measured in the appropriate plasma cholesterol sample.
D000818:Animals; D002250:Carbon Radioisotopes; D002784:Cholesterol / Q000008:administration & dosage / Q000378:metabolism*; D003903:Deuterium; D005243:Feces / Q000032:analysis*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D011865:Radioisotope Dilution Technique; D051381:Rats; D011919:Rats, Inbred Strains; D013261:Sterols / Q000032:analysis*; D014316:Tritium
D002250:Carbon Radioisotopes; D013261:Sterols; D014316:Tritium; D002784:Cholesterol; D003903:Deuterium