Gray T K, McAdoo T, Pool D, Lester G E, Williams M E, Jones G
Clin Chem. 1981 Mar;27(3):458-63.
A radioimmunoassay for 1,25-dihydroxycholecalciferol which did not cross react with 1,25-dihydroxyergocalciferol is described. IgG fractions were prepared from the serum of rabbits that had been immunized with 1,25-dihydroxycholecalciferol-3-hemisuccinate coupled to bovine albumin. Radioligand binding by the IgG fractions was time-, temperature-, and pH-dependent. The IgG fractions had a high affinity for 1,25-dihydroxycholecalciferol but cross reacted with 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol. Vitamin D2 metabolites did not cross react in the assay when amounts up to 9 ng per tube were tested. The determination of 1,25-dihydroxycholecalciferol in human serum required an organic extraction and chromatographic isolation of the metabolite. Radioligand binding was influenced by the presence and concentration of the proteins in the phosphate buffer. The mean concentration of 1,25-dihydroxycholecalciferol in serum from normal adults was 56 (SEM 5.7) ng/L. 1,25-Dihydroxycholecalciferol was not detectable in serum from a nephrectomized subject and the concentration in serum was lower than normal in hypoparathyroid patients. Ingestion of 1,25-dihydroxycholecalciferol by nephrectomized or hypoparathyroid patients restored the concentration of 1,25-dihydroxycholecalciferol in serum to the normal range. The stability of the IgG fraction, the relatively short incubation interval, and the ability to measure 1,25-dihydroxycholecalciferol without interference from 1,25-dihydroxyergocalciferol are unique aspects of this radioimmunoassay.
本文描述了一种用于1,25 - 二羟胆钙化醇的放射免疫测定法，该方法与1,25 - 二羟麦角钙化醇无交叉反应。从用与牛血清白蛋白偶联的1,25 - 二羟胆钙化醇 - 3 - 半琥珀酸免疫的兔血清中制备IgG组分。IgG组分的放射性配体结合具有时间、温度和pH依赖性。IgG组分对1,25 - 二羟胆钙化醇具有高亲和力，但与25 - 羟胆钙化醇和24,25 - 二羟胆钙化醇有交叉反应。当每管测试量高达9 ng时，维生素D2代谢物在该测定中无交叉反应。测定人血清中的1,25 - 二羟胆钙化醇需要对该代谢物进行有机萃取和色谱分离。放射性配体结合受磷酸盐缓冲液中蛋白质的存在和浓度影响。正常成年人血清中1,25 - 二羟胆钙化醇的平均浓度为56（标准误5.7）ng/L。在肾切除患者的血清中未检测到1,25 - 二羟胆钙化醇，甲状旁腺功能减退患者血清中的浓度低于正常水平。肾切除或甲状旁腺功能减退患者摄入1,25 - 二羟胆钙化醇可使血清中1,25 - 二羟胆钙化醇的浓度恢复到正常范围。IgG组分的稳定性、相对较短的孵育间隔以及能够在不受1,25 - 二羟麦角钙化醇干扰的情况下测量1,25 - 二羟胆钙化醇是该放射免疫测定法的独特之处。
