Retinol metabolism

Retinol metabolism is the complex biochemical pathway responsible for the uptake, storage, and conversion of Vitamin A (retinol) into its biologically active metabolites, primarily 11-cis-retinal and all-trans-retinoic acid (ATRA) (StatPearls: Vitamin A, 2023; NIH ODS, 2022). This pathway involves a series of enzymatic reactions mediated by retinol dehydrogenases (RDHs), retinaldehyde dehydrogenases (RALDHs), and lecithin:retinol acyltransferase (LRAT), as well as transport by retinol-binding proteins (RBPs) (Nutrients, 2020). The active metabolite 11-cis-retinal is essential for the visual cycle in the retina, while ATRA serves as a ligand for nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which act as transcription factors to regulate genes involved in cell growth, differentiation, and apoptosis (Chem Rev, 2014). Although Retinol metabolism refers to a biological process rather than a single molecular target, its components are critical in clinical medicine. Pharmacological interventions often utilize synthetic retinoids that mimic these metabolites to treat acne, psoriasis, and acute promyelocytic leukemia, though these therapies are limited by significant safety concerns, most notably severe teratogenicity.

Other names

Vitamin A metabolismRetinoid metabolismRetinoid cycleRetinoid signaling pathway

Retinoids act as ligands for nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which function as transcription factors to regulate gene expression. Some drugs also inhibit the degradation of retinoic acid or influence the enzymatic conversion of retinol to its active metabolites.