A form of vitamin a with formula C20H28O, found mainly in the retina and liver of freshwater fish
Vitamin a is a fat-soluble vitamin and is essential in the following metabolic processes and functions: night vision, gene transcription, bone metabolism, immune function, antioxidant, embryonic development, epithelial tissue protection, and hematopoiesis. There are many forms of vitamin A. One of them is the widely known retinol or vitamin A1. It is yellow in color and with a formula, C20H30O. It is present in fish oils and green vegetables. Another form of vitamin A is dehydroretinol (or vitamin A2). It is also yellow in colour and with similar function. Its formula is C20H28O. Having an extra double bond in the 3-4 position of the cyclohexane ring makes dehydroretinol different from retinol.1 Dehydroretinol is found chiefly in the retina and liver of freshwater fish and certain invertebrates and amphibians.2 It should not be confused with dehydroretinal. The latter is the aldehyde of dehydroretinol.
1 dehydroretinol. (n.d.) Medical Dictionary for the Dental Professions. (2012). Retrieved from []
2 dehydroretinol. (n.d.) Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. (2003). Retrieved from []