Description | Lumisterol 3 is a normal human secosterooid metabolite from the class of vitamin D3 photoisomer derivatives. It is synthesized from 7-Dehydrocholesterol in the epidermis in response to ultraviolet irradiation. When human skin is exposed to ultraviolet radiation, epidermal 7-dehydrocholesterol is converted to previtamin D, and during prolonged exposure, the synthesis of previtamin D3 reaches a plateau at about 10 to 15 percent of the original 7-dehydrocholesterol content, and previtamin D3 is photoisomerized to two biologically inert isomers and lumisterol 3 is one of them (the other one being lumisterol 3). Therefore, lumisterol 3 is a metabolite to chronic exposure to sunlight. Lumisterol 3, as well as other photoisomers of vitamin D3 and previtamin D3 has been demonstrated to have inhibited keratinocyte proliferation. Thus, sunlight provides vitamin D3 photoproducts that may act directly to regulate epidermal proliferation and differentiation under physiologic conditions. (PMID 6256855, 10876100) |