title: Isolation and identification of tachysterol3 in rat skin exposed to ultraviolet light.
abstract: In order to investigate the mechanism of the cutaneous synthesis of vitamin D3 in vivo, a photolysis by-product of previtamin D3 in organic solvent, namely, tachysterol3 was isolated and identified in ultraviolet-exposed rat skin. Tachysterol3 was identified by chromatographic comigration of an ultraviolet-absorbing peak wih authentic tachysterol3 in straight-phase HPLC (Zorbax SIL column) and reversed-phase HPLC (Nucleosil 5C18 column), and by  the ultraviolet absorption spectrum. The comparison of the extent of formation of tachysterol3 between in rat skin in vivo and in ethanol solution indicated that the yield in rat skin is similar to that in organic solvent. The results suggest that the reaction mechanism in rat skin in vivo may be identical wit  that in organic solvents.
mesh_terms: D000818:Animals; D002762:Cholecalciferol / Q000031:analogs & derivatives; D002851:Chromatography, High Pressure Liquid; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012867:Skin / Q000528:radiation effects*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002762:Cholecalciferol; C025168:previtamin D(3)