7-dehydrocholesterol

Description: 7-Dehydrocholesterol (7DHC) is a zoosterol that functions a precursor for the biosynthesis of cholesterol and vitamin D3. It is photochemically converted to vitamin D? in the skin, therefore functioning as provitamin-D?. The presence of this compound in human skin enables humans to manufacture vitamin D? from ultraviolet rays in the sun light, via an intermediate isomer pre-vitamin D?. It is also found in the milk of several mammalian species. Lanolin, a waxy substance that is naturally secreted by wool-bearing mammals, contains 7-DHC which is converted into vitamin D by sunlight and then ingested during grooming as a nutrient. In insects it is a precursor for the hormone ecdysone, required for reaching adulthood. It was discovered by Nobel-laureate organic chemist Adolf Windaus.

References: Oxysterolsfrom free radical chain oxidation of 7-dehydrocholesterol: product andmechanistic studies. J Am Chem Soc. 2010 Feb 24; 132(7):2222-32.