Taurocholate Metabolism in Man

Abstract

Tracer doses of ³⁵S-tauro-7-³H-cholate were given to 9 healthy volunteers and duodenal aspirates from the subsequent 7 days were examined. Specific radioactivities of both isotopes were determined. An average taurocholate pool of 0.9 ± 0.3 (S.D.) g, an average half life of 2.1 ± 1.0 (S.D.) days and a daily synthesis of taurocholate of 0.32 ± 0.14 (S.D.) g were found. The difference between the fractional turnover rate constant for the bile acid nucleus radioactivity and the taurine radioactivity expresses the fractional deconjugation rate and was found to be 10 ± 6 (S.D.) % day ^-1. The 7-α-dehydroxylation rate expressed as the percentage of the total bile acid radioactivity present in the deoxycholate fractions was found to be 5.8 ± 2.4 (S.D.)% day^-1. After peroral administration of 10 μC ³⁵S-taurine, virtually no radioactivity was found in the taurine-conjugated bile salts. A glycine-taurine ratio of 1.5 ± 0.8 (S.D.), a trihydroxy-dihydroxy bile acid ratio of 1.0 ± 0.3 (S.D.), and a cholate-deoxycholate ratio of 2.0 ± 1.0 (S.D.) were found.

Key-words:

• Deconjugation
• 7-α-dehydroxylation
• elimination
• relative concentrations
• taurocholate
• taurodeoxycholate