Metabolism of (24R and 24S)-27-nor-24-methyl-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acids and 27-nor-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acid in guinea pigs.

[7beta-3H]-(24R and 24S)-27-nor-24-methyl-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acids and [7beta-3H]-27-nor-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acid (C27 and C26 bile acids having the same nuclear configuration as cheno-deoxycholic acid and its precursor, 3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic-acid) were synthesized and administered intraperitoneally to bile fistula guinea pigs. The biliary bile acids formed were hydrolyzed and analyzed by thin layer chromatography, and the metabolites were identified by the inverse isotope dilution method. The results showed that both (24R and 24S)-27-nor-24-methyl-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acids were not metabolized by the liver and were excreted unchanged as their taurine and glycine conjugates whereas 27-nor-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acid was converted to chenodeoxycholic acid.