Retinoic acid metabolism.

The tissue distribution of retinoic acid (RA) throughout development is highly restricted, defined by the expression patterns of enzymes involved in RA synthesis and catabolism. Presented is a summary of recent research that examines the role of some of the enzymes involved in RA distribution, particularly those involved in RA catabolism (P450RAI). These latter enzymes protect against premature exposure to RA, and the implications of these findings are discussed.