Abstract
The intestinal calcium transport activity and serum calcium and phosphorous concentrations of vitamin D-deficient rats were increased by irradiation with an ultraviolet (UV) lamp. The existence of 25-hydroxyvitamin D3 (25-OH-D3) in their bloods and livers was physicochemically confirmed by high-performance liquid chromatography (HPLC), gas-liquid chromatography (GLC) and mass fragmentography, whereas the compound could not be detected in the tissues of nonirradiated rats. The results strongly suggested that vitamin D3 in vivo generated in irradiated rat skin might be normally metabolized 'and utilized to prevent rickets. The level of 25-OH-D3 in the tissues was determined by a HPLC method.
