期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1979
卷号：25
期号：5
页码：385-398
DOI：10.3177/jnsv.25.385
出版社：Center for Academic Publications Japan
摘要：In order to develop the investigations into photobiogenesis of vitamin D3, a rapid and precise method for the determination of the vitamin in rat skin was established by using high-performance liquid chromatography (HPLC). The proposed method included saponification of small pieces of rat skin, extraction of the unsaponifiable matter and application to HPLC using “Zorbax SIL” (straight-phase) as an adsorbent and 0.5% isopropanol in n -hexane as a mobile phase. The applicable lower limit of the method was 2ng of vitamin D3/cm2 of subcutaneous tissue-removed skin and it was possible to assay a concentration higher than 2ng/cm2. The proposed method was applied to determine the content of vitamin D3 in rat skin obtained from in vivo and in vitro irradiation experiments. In the in vitro experiment, the yield of vitamin D3 increased in proportion to the irradiation time. On the other hand, the yield in the in vivo experiment showed a proportional increase similar to the in vitro experiment until 60min irradiation, while a nearly constant value was obtained by irradiation for longer than 60min. When the rat skin obtained from the in vitro experiment was irradiated with monochromatic UV rays in the range 260-350nm, the most effective wavelength for the formation of vitamin D3 was confirmed to be 303nm, which differs from the result obtained from the experiment in a test tube (295nm). Moreover, the yield of vitamin D3 by irradiation with UV rays below 288nm was extremely low, which again differed from the results of a test tube experiment. These differences were thought to be due to the filter effect of the malpighian layer in the epidermis of rat skin.
