part_of metabolic pathway pertinent to the brain retinoid metabolic pathway 2012-06-04T10:52:32Z PW:0001003 Retinoid metabolism and transport Those metabolic reactions involving the fat-soluble vitamin A and its metabolites. Vitamin A, retinol and vitamin A activities of metabolites such as retinal and retinoic acids are essential for visual transduction as well as for neuro and immune system functions and epithelial differentiation. Plants and microorganisms can synthesize vitamin A de novo while higher organisms derive it from diet as precursors of carotenoids or retinyl esters. pathway retinoid metabolic process vitamin A metabolic pathway vpetri vitamin A homeostasis fat-soluble vitamin metabolic pathway