Jones G, Byrnes B, Palma F, Segev D, Mazur Y
J Clin Endocrinol Metab. 1980 Apr;50(4):773-5. doi: 10.1210/jcem-50-4-773.
24(R),25-Dihydroxyergocalciferol [24,25-(OH)2-D2] is 1.7 times less potent than 24 (R), 25-(OH)2D3, 25-Hydroxyvitamin D2 (25OHD2), or 25OHD3 in the displacement of (3H)25OHD3 from rat serum binding proteins. 1,25-(OH)2D2 is 1.3 times less potent than 1,25-(OH)2D3 in the displacement of (3H)1,25-(OH)2D3 from a chick intestinal binding receptor. In light of binding affinity and chromatographic differences between vitamin D3 and its D2 analogs, it is our view that methods which purport to measure 1,25-(OH)2D and 24,25-(OH)2D probably understimate the contributions of D2 metabolites. This is particularly important in the case of plasma extracts from patients given large doses of vitamin D2.
24（R），25 - 二羟基麦角钙化醇[24,25 - （OH）₂ - D₂]在从大鼠血清结合蛋白上置换（³H）25 - 羟基维生素D₃（25OHD₃）方面的效力比24（R），25 - 二羟基胆钙化醇[24,25 - （OH）₂D₃]、25 - 羟基维生素D₂（25OHD₂）或25OHD₃低1.7倍。1,25 - （OH）₂D₂在从小肠结合受体上置换（³H）1,25 - （OH）₂D₃方面的效力比1,25 - （OH）₂D₃低1.3倍。鉴于维生素D₃与其D₂类似物之间的结合亲和力和色谱差异，我们认为，那些旨在测量1,25 - （OH）₂D和24,25 - （OH）₂D的方法可能低估了D₂代谢产物的贡献。这在给予大剂量维生素D₂的患者的血浆提取物中尤为重要。
