retinol Vitamin A: Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of CAROTENOIDS found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products.. vitamin A : Any member of a group of fat-soluble retinoids produced via metabolism of provitamin A carotenoids that exhibit biological activity against vitamin A deficiency. Vitamin A is involved in immune function, vision, reproduction, and cellular communication.. all-trans-retinol : A retinol in which all four exocyclic double bonds have E- (trans-) geometry.. retinol : A retinoid consisting of 3,7-dimethylnona-2,4,6,8-tetraen-1-ol substituted at position 9 by a 2,6,6-trimethylcyclohex-1-en-1-yl group (geometry of the four exocyclic double bonds is not specified). | 2.9 | 4 | 0 | retinol; vitamin A | human metabolite; mouse metabolite; plant metabolite |