Retinoyl Glucuronide and Other Metabolites

The plasma concentration of retinoyl glucuronide is between 5 and 14 mnol per L, and the activity of retinoic acid UDP-glucuronyltransferase increases in vitamin A deficiency, suggesting that glucuronidation may be important 

Anhydroretinol may arise by nonenzymic isomerization of all-trans-retinol under acidic conditions and can act as a precursor for the synthesis of other biologically active retroretinoids (McBee et al., 2000). 

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