title: Metabolism of 13-cis-retinoic acid by a rat liver 9000g supernatant preparation.
abstract: The in vitro metabolites formed on incubation of 13-cis-retinoic acid (13-cis-RA, isotretinoin) with a 9000g rat liver supernatant system were isolated by HPLC and identified by their mass and NMR spectra. The major metabolic pathway was hydroxylation at C4 to give 4-hydroxy-13-cis-RA, which was rapidly oxidized to 4-oxo-13-cis-RA, the major isolated metabolite. Further metabolism of this 4-oxo metabolite led to two novel compounds, 2-hydroxy-4-oxo-13-cis-RA and 3-hydroxy-4-oxo-13-cis-RA. In addition, small amounts of 13-cis-RA and 4-oxo-13-cis-RA were enzymatically converted to their all-trans isomers. Support for these pathways was obtained by the metabolism of reference samples of 4-hydroxy-13-cis-RA, 4-oxo-13-cis-RA, all-trans-RA, and 4-oxo-all-trans-RA. The predominant formation of 4-oxo metabolites of 13-cis-RA in this in vitro rat system and the results from previously reported in vivo metabolism studies suggest that oxidation at C4 is a major metabolic pathway of 13-cis-RA in both rats and humans.
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D066298:In Vitro Techniques; D015474:Isotretinoin; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051381:Rats; D014212:Tretinoin / Q000378:metabolism*
chemical_list: D014212:Tretinoin; D015474:Isotretinoin