食品,生体試料中のビタミンD並びに関連化合物の徴量分析と栄養学への応用に関する研究

抄録

Procedures for the qualitative and quantitative analysis of vitamin D and related compounds in foods, skin, plasma and other biological materials were established and the following results were obtained : (1) The formation of previtamin D_3, vitamin D_3 and tachysterol_3 in the skin of vitamin D-deficient rats irradiated with ultraviolet (UV) light was physicochemically confirmed by gas-liquid chromatography/mass spectrometry (GC-MS) and/or high-performance liquid chromatography (HPLC). The experimental results showed that the endogenous 7-dehydrocholesterol in the skin was photo-chemically and thermally isomerized to vitamin D_3 via previtamin D_3 in the same manner as in a test tube. (2) The major circulating metabolite of vitamin D in human plasma is 25-hydroxyvitamin D (25-OH-D) and its concentration directly reflects the repletion status of vitamin D nutrition. We assayed the concentrations of exogenous 25-OH-D_2 and endogenous 25-OH-D_3 in the plasma samples obtained from about 1,000 subjects including adults, mothers, infants and children, and very interesting results were obtained. (3) We established a HPLC method for micro-determination of vitamin D in foods, feeds and pharmaceuticals using reversed-phase and straight-phase columns. The proposed method was confirmed to be useful for many kinds of samples.