Investigations on metabolites of vitamin D in rat bile. Separation and partial identification of a major metabolite

1. Young rats with cannulated bile ducts were given 0.34mg. of [1alpha-(3)H]cholecalciferol or 0.54mg. of [(14)C]ergocalciferol by intravenous infusion. Of the radioactivity in the dose of [1alpha-(3)H]cholecalciferol 31% was recovered in bile within 24hr. 2. The metabolites in bile were separated by gradient-elution column chromatography on silicic acid into five components, all more polar than cholecalciferol or 25-hydroxycholecalciferol. [(14)C]Ergocalciferol gave a similar pattern of metabolites in bile. 3. The three most polar metabolites were shown to be ionic. The major component has been identified as a glucuronide conjugate, which was not identical with synthetic cholecalciferyl glucuronide.