vitamin D synthesis
process whereby 7-dehydrocholesterol, precursor of vitamin D3, produces previtamin D3 by absorbing 240 nm to 315 nm ultraviolet radiation and moreover changes it to vitamin D3 through a thermal isomerization process
Note 1 to entry: Vitamin D is a generic term for vitamin D2 and/or vitamin D3. Vitamin D synthesis in mammalian skin produces vitamin D3. Vitamin D2 is formed in plants in an analogous process when ultraviolet radiation activates ergosterol.
Note 2 to entry: This entry was numbered 17-1420 in CIE S 017:2011.