previtamin

previtamin

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1,2] Ultraviolet (UV) B radiation with a wavelength of 290-320 nanometres penetrates uncovered skin and converts cutaneous 7-dehydrocholesterol to previtamin [D.
Photometabolism of 7-dehydrocholesterol to previtamin D3 in skin," Biochemical and Biophysical Research Communications, vol.
UVB radiation catalyzes conversion of 7-dehydrocholesterol to previtamin D, which then thermally converts to vitamin D.
These rays trigger the production of a vitamin D precursor found in skin called previtamin D3, which is then activated in the liver and kidneys.
During exposure to sunlight, ultraviolet photons enter the skin and convert 7-dehydrocholesterol to previtamin D3, which, in turn, is converted to vitamin D3.
26) Oystercatchers may also display various physiologic mechanisms for controlling vitamin D metabolism, including inadequate cutaneous production, enhanced cutaneous destruction of previtamin [D.
Ultraviolet rays from the sun hit the precursor in the skin and convert it to previtamin D3.
The main source of vitamin D in humans is solar UV-B (290-315 nm wavelengths) radiation, which influences the formation of previtamin D in the skin (cholecalciferol).
Because most dietary products are low in vitamin D, the major source is ultraviolet B (UVB) radiation, which penetrates the skin and converts 7-dehydrocholesterol to 25-hydroxycholecaldferol vitamin D3 (25-OHVitD) via previtamin D.
Solar ultraviolet B photons are absorbed by 7-dehydrocholesterol in the skin, leading to its transformation to previtamin D3, which is rapidly converted to vitamin D3.
Solar radiation in the UVB waveband (wavelength, 290 to 315 nm) converts 7-dehydrocholesterol to previtamin D3 which is converted to vitamin D3 (1-5).