title: Measurement of circulating vitamin D in man.
abstract: An assay for vitamin D consisting of high-pressure liquid chromatography (HPLC) and ultraviolet (UV) absorbance detection has been developed and used to measure circulating vitamin D concentrations in human subjects during summer and winter and after deliberate exposure to ultraviolet radiation. Extracts of 2-4 ml of serum were initially fractionated on silica Sep-Pak cartridges followed by reverse-phase HPLC and finally quantitated by UV-absorbance during straight-phase HPLC. Using these methods, we determined the normal range for circulating vitamin D in Boston subjects to be less than 0.5 ng/ml to 25 ng/ml (n = 30); subjects sampled during summer months had higher concentrations of vitamin D than those sampled during winter months. In subjects exposed to a single quantitative dose of ultraviolet radiation (UVR), large transient increases in circulating vitamin D3 were observed. Concentrations rose 30-50 fold over the first days after exposure before returning to basal levels by one week.
mesh_terms: D000328:Adult; D001667:Binding, Competitive; D002762:Cholecalciferol / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004872:Ergocalciferols / Q000097:blood; D006801:Humans; D007700:Kinetics; D011485:Protein Binding; D012621:Seasons; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000097:blood* / Q000528:radiation effects; D014916:Whole-Body Irradiation
chemical_list: D004872:Ergocalciferols; D014807:Vitamin D; D002762:Cholecalciferol