| Summary: | After the intraportal injection of retinoic acid-15-14C into rats, all-trans methyl retinoate, a cis isomer of methyl retinoate, retinoyl β-glucurono-γ-lactone, retinoic acid, and retinoyl β-glucuronide were isolated from methanol extracts of rat bile by chromatography on anion-exchange resin and silicic acid columns and characterized on thin-layer plates of Silica Gel G. On the other hand, when bile was extracted with n-butanol or analyzed directly by thin-layer chromatography, only retinoyl βglucuronide and a very small amount of retinoic acid could be detected. Butanol extracts of the liver and the intestine, however, still contained a small radioactive nonpolar fraction. When retinoyl β-glucuronide was incubated with an anion-exchange resin in the presence of methanol, several nonpolar products appeared. Apparently the methyl retinoate, retinoyl β-glucurono-γ-lactone, and most of the retinoic acid previously found in bile after retinoic acid administration are produced from retinoyl β-glucuronide during the isolation procedure.
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