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Simultaneous determination of pool sizes and fractional turnover rates, of deoxycholic acid, cholic acid and chenodeoxycholic acid in man by isotope dilution with 2H and 13C labels and serum sampling

✍ Scribed by F. Stellaard; M. Sackmann; F. Berr; G. Paumgartner


Publisher
John Wiley and Sons
Year
1987
Tongue
English
Weight
321 KB
Volume
14
Category
Article
ISSN
1076-5174

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✦ Synopsis


This paper describes a method for simultaneous determination of the kinetics of the three major bile acids in man using (2,2,4,4-'H4) deoxycholic acid, (24-13C) cholic acid and (24-13C) chenodeoxycholic acid. The gas chromatographichass spectrometric-selected ion monitoring technique used provided complete separation of deoxycholic acid, cholic acid and chenodeoxycholic acid, which permitted simultaneous measurement of isotope ratios for all three bile acids. Since measurement of all three pool sizes and fractional turnover rates in a single experiment requires different isotopic labels for deoxycholic acid and cholic acid, we investigated the in uiuo stability and applicability of (2,2,4,4-'H,) deoxycholic acid as a stable isotope marker for isotope dilution studies in man. No consistent differences were observed between deoxycholic acid pool sizes and fractional turnover rates determined in serum samples after administration of (2,2,4,4-'H4) deoxycholic acid and (24-I3C) deoxycholic acid. Simultaneous administration of (2,2,4,4-'H4) deoxycholic acid, (24-13C) cholic acid and (24-13C) chenodeoxycholic acid and isotope ratio measurements in serum permitted determination of pool sizes and fractional turnover rates of the three major bile acid and the 7or-dehydroxylation fraction. Pool sizes, fractional turnover rates and synthesis rates (input rates) agreed well with data obtained previously with (24-%) labels in independent studies.