Synthesis and metabolism of sodium 3α,7α-dihydroxy-25,26-bishomo-5β-cholane-26-sulfonate in the hamster

This paper reports the chemical synthesis of a new bile acid analogue, namely sodium 3α,7α-dihydroxy-25,26-bishomo-5β-cholane-26-sulfonate (bishomoCDC-sul) from chenodeoxycholic acid and describes its metabolism in the hamster. The structure of the new compound was confirmed by proton and carbon-13 nuclear magnetic resonance spectroscopy. After intravenous infusion of [3H]-labeled sulfonate into bile fistula hamsters, it was extracted by the liver and secreted into the bile; more than 65% of the radioactivity was recovered in the bile within 1 h. Following intraduodenal administration of the [3H]sulfonate and [14C]chenodeoxycholyltaurine, both compounds were excreted into the bile more slowly; only 41 and 43% of the radioactivity, respectively, were recovered in the bile during the four-hour experimental period. In contrast, when the labeled compounds were injected into the terminal ileum, both the sulfonate and chenodeoxycholyltaurine were repidly absorbed and secreted into the bile; 84 and 97%, respectively, of the radioactivity were recovered during a four-hour period. Chromatographic analysis demonstrated that in these short-term experiments most (>95%) of the sulfonate was secreted into the bile without biotrasformation regardless of the route of administration. When infused intravenously at increasing doses, bishomoCDC-sul induced cholestasis at an infusion rate of 1 μmol/min/kg. These results suggest that sodium 3α,7α-dihydroxy-25,26-bishomo-5β-cholane-26-sulfonate was absorbed from the terminal ileum by active transport, extracted by the liver, and secreted into the bile in a manner similar to that of the natural bile acids.