Papapoulos S E, vd Berg H, Frölich M, Valentijn R M
Department of Endocrinology, University Hospital Leiden, The Netherlands.
Nephrol Dial Transplant. 1988;3(5):647-50. doi: 10.1093/oxfordjournals.ndt.a091721.
The formation of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) after single intravenous injections of 1 alpha-hydroxycholecalciferol (1 alpha-OHD3) was examined in four patients with chronic renal failure on regular haemodialysis. Following 1-3 micrograms 1 alpha-OHD3, administered at weekly intervals, 1,25-(OH)2D3 appeared in the circulation within 1 h, and peak concentrations were reached between 2 h and 5 h. By 8 h serum 1,25-(OH)2D3 concentrations had started declining and by 44 h they had returned to baseline after 1 microgram 1 alpha-OHD3, but they were still above basal after 2 and 3 micrograms by an average of 30 pmol/l. One week after injections, concentrations were back to basal in all patients studied. The serum 1,25-(OH)2D3 dose response to injected 1 alpha-OHD3 was linear, indicating ample capacity of the liver 25-hydroxylase to further hydroxylate 1 alpha-OHD3. However, examination of the individual responses revealed lower increments in serum 1,25-(OH)2D3 concentrations in the patients with the highest basal serum 25-hydroxyvitamin D concentrations. Intravenous 1 alpha-OHD3 may be useful in the further study of the interactions between 1,25-(OH)2D3, calcium and PTH in chronic renal failure, as well as of the hepatic metabolism of vitamin D.
对4例接受定期血液透析的慢性肾衰竭患者静脉单次注射1α-羟胆钙化醇（1α-OHD3）后1,25-二羟胆钙化醇（1,25-(OH)2D3）的形成情况进行了研究。每周间隔给予1 - 3微克1α-OHD3后，1,25-(OH)2D3在1小时内出现在循环中，2至5小时达到峰值浓度。8小时时血清1,25-(OH)2D3浓度开始下降，注射1微克1α-OHD3后44小时恢复至基线水平，但注射2微克和3微克后，血清浓度仍比基础水平平均高30 pmol/l。注射一周后，所有研究患者的浓度均恢复至基础水平。血清1,25-(OH)2D3对注射1α-OHD3的剂量反应呈线性，表明肝脏25-羟化酶有足够能力将1α-OHD3进一步羟化。然而，对个体反应的检查发现，基础血清25-羟维生素D浓度最高的患者血清1,25-(OH)2D3浓度升高幅度较低。静脉注射1α-OHD3可能有助于进一步研究慢性肾衰竭中1,25-(OH)2D3、钙和甲状旁腺激素之间的相互作用，以及维生素D的肝脏代谢。
