麦角钙化醇

麦角钙化醇（英語：Ergocalciferol）是维生素D2的化学名，为麦角固醇在紫外线作用下产生的开环甾体（英语：secosteroid）。早期制备的麦角钙化醇商品名为Viosterol，由麦角固醇在紫外线光照下制成，含光固醇（英语：Lumisterol）杂质。麦角钙化醇是一种维生素D膳食补剂，可以治疗吸收不良、肝病造成的维生素D缺乏症。此药还可用于甲状腺功能减退造成的低血钙症。麦角钙化醇可口服、肌注，在一些蘑菇中天然产生。 过量使用麦角钙化醇可造成多尿、高血压、肾结石、肾衰竭、乏力、便秘。长期高剂量使用可造成组织钙化（英语：tissue calcification），因此建议此类人群监测血钙含量。孕妇可以安全使用正常剂量。麦角钙化醇增加肠道、肾脏吸收的钙质。 麦角钙化醇最早于1936年发现描述。此物名列世界卫生组织基本药物标准清单，为健保系统（英语：health system）所需的有效、安全药物之一。麦角钙化醇为非处方药，且有通用名药物版本。在英国，此药对國民保健署的一般开支不足每处方每月10英镑。有些国家会在早餐麦片和麦淇淋等食物中加入麦角钙化醇。 和晒太阳产生的胆钙化醇（维生素D3）一样，维生素D2可以用于补充维生素D。 之前一般认为两种维生素D效果类似，因其在改善佝偻病、降低年长患者跌倒的概率上效果相似。现在对于维生素D2和D3在体内行为是否相似，和生成骨化三醇这种激素的效率，有相互矛盾的一些研究。一些初期研究表明维生素维生素D3效率更高，而其它的研究则表明两者效率类似。维生素D2和D3的新陈代谢路径稍有不同；有研究指出维生素D结合蛋白对维生素D3所形成的骨化三醇有更大亲和力。有汇总分析指出，D3更适合提高血浆25-(OH)D浓度，但也有研究说明两者在维持浓度方面效果相当。 有研究发现奥兹海默症患者体内的麦角钙化醇含量较低，但这项研究并未提及这一结果和食品中麦角钙化醇缺乏是否有关。 麦角钙化醇和胆钙化醇（D3）的作用机理大致相类。麦角钙化醇本身不具活性，需经过两次羟化才可具有活性：第一步羟化在肝内经过CYP2R1（英语：CYP2R1）生成25-羟基麦角钙化醇（麦角骨化二醇，25-OH D2），第二部在肾内经CYP27B1转化为1,25-二羟基麦角钙化醇（麦角骨化三醇，1,25-(OH)2D2）。与胆钙化醇不同，麦角钙化醇不由CYP27A1羟化。 与D3的对应物比较，麦角钙化醇和各种代谢产物对维生素D结合蛋白（英语：vitamin D-binding protein）的亲和力较低。麦角骨化三醇对骨化三醇受体（英语：vitamin D receptor）的亲和力与骨化三醇相类。麦角钙化醇及其产物可经24-羟化失效。 麦角钙化醇最早从麦角中提取，故而得名。现在使用苔藓、真菌和苜蓿进行中波紫外线照射就可以提取麦角钙化醇。以下列出一些食品内的含量： 真菌 雙孢蘑菇（D2 + D3）： 褐熟（portabello），生：0.3 μg（10 IU）；光照后：11.2 µg（446 IU） 幼褐（crimini），生：0.1 μg（3 IU）；光照后：31.9 µg（1276 IU） 香菇： 生：维生素 D (D2 + D3)：0.4 μg (18 IU) 干货：维生素 D (D2 + D3)：3.9 μg (154 IU) 在真菌中，麦角钙化醇由麦角固醇受紫外光照射产生。人类可以吸收利用高D2酵母制成的面包中的维生素D。食用紫外光（UV-B）照过的双孢蘑菇可以改善维生素D缺乏，其作用与维生素D2补充剂效果相类。此类光照处理不会将蘑菇漂白。西方记者发新闻称，一份普通食量（6 g 干重，约合 60 g）的双胞蘑菇经过短波紫外光照射5分钟后可以提供3,500 IU的维生素D，引来多方关注。 工业上，麦角钙化醇由酵母中提取的麦角固醇经紫外光照射和提纯制成。 Science Service (1930) Viosterol official name for irradiated ergosterol, J. Chem. Educ. 7(1) 166, DOI: 10.1021/ed007p166, see [pubs.acs.org/doi/abs/10.1021/ed007p166, accessed 10 July 2014. Coulston, Ann M.; Boushey, Carol; Ferruzzi, Mario. Nutrition in the Prevention and Treatment of Disease. Academic Press. 2013: 818 [2018-04-09]. ISBN 9780123918840. （原始内容存档于2016-12-30） （英语）.  WHO Model Formulary 2008 (PDF). World Health Organization. 2009: 498 [2016-12-08]. ISBN 9789241547659. （原始内容存档 (PDF)于2016-12-13）.  British national formulary : BNF 69 69. British Medical Association. 2015: 703–704. ISBN 9780857111562.  Office of Dietary Supplements - Vitamin D. ods.od.nih.gov. 2016-02-11 [2016-12-30]. （原始内容存档于2016-12-31）.  Ergocalciferol. The American Society of Health-System Pharmacists. [2016-12-08]. （原始内容存档于2016-12-30）.  Hamilton, Richart. Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition. Jones & Bartlett Learning. 2015: 227. ISBN 9781284057560.  Fischer, Janos; Ganellin, C. Robin. Analogue-based Drug Discovery. John Wiley & Sons. 2006: 451 [2018-04-09]. ISBN 9783527607495. （原始内容存档于2016-12-30） （英语）.  WHO Model List of Essential Medicines (19th List) (PDF). World Health Organization. April 2015 [2016-12-08]. （原始内容存档 (PDF)于2016-12-13）.  Feral, Priscilla; Hall, Lee; Animals, Friends of. Dining with Friends: The Art of North American Vegan Cuisine. Friends of Animals/Nectar Bat Press. 2005: 160 [2018-04-09]. ISBN 9780976915904. （原始内容存档于2016-12-31） （英语）.  Bennett, Beverly; Sammartano, Ray. The Complete Idiot's Guide to Vegan Living, Second Edition. Penguin. 2012: Chapter 15 [2018-04-09]. ISBN 9781615642793. （原始内容存档于2016-12-30） （英语）.  Holick, Michael F.; Binkley, Neil C.; Bischoff-Ferrari, Heike A.; Gordon, Catherine M.; Hanley, David A.; Heaney, Robert P.; Murad, M. Hassan; Weaver, Connie M. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology & Metabolism (The Endocrine Society). 2011, 96 (7): 1911–1930. ISSN 0021-972X. doi:10.1210/jc.2011-0385.  Thacher, TD; Fischer, PR; Obadofin, MO; Levine, MA; Singh, RJ; Pettifor, JM. Comparison of Metabolism of Vitamins D2 and D3 in Children with Nutritional Rickets. Journal of Bone and Mineral Research. 2010, 25 (9): 1988–1995. PMC 3153403 . PMID 20499377. doi:10.1002/jbmr.99.  Susan M. Fosnight, William J. Zafirau, Susan E. Hazelett. Vitamin D supplementation to prevent falls in the elderly: evidence and practical considerations. Pharmacotherapy. 2008-02, 28 (2): 225–234 [2019-02-12]. ISSN 0277-0008. doi:10.1592/phco.28.2.225. （原始内容存档于2019-10-18）.  Lisa A. Houghton, Reinhold Vieth. The case against ergocalciferol (vitamin D2) as a vitamin supplement. The American Journal of Clinical Nutrition. 2006-10, 84 (4): 694–697 [2019-02-12]. ISSN 0002-9165. PMID 17023693. doi:10.1093/ajcn/84.4.694. （原始内容存档于2020-04-25）.  H. M. Trang, D. E. Cole, L. A. Rubin, A. Pierratos, S. Siu, R. Vieth. Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2. The American Journal of Clinical Nutrition. 1998-10, 68 (4): 854–858 [2019-02-12]. ISSN 0002-9165. PMID 9771862. doi:10.1093/ajcn/68.4.854. （原始内容存档于2020-04-25）.  Holick, Michael F.; Biancuzzo, Rachael M.; Chen, Tai C.; Klein, Ellen K.; Young, Azzie; Bibuld, Douglass; Reitz, Richard; Salameh, Wael; Ameri, Allen; Tannenbaum, Andrew D. Vitamin D2Is as Effective as Vitamin D3in Maintaining Circulating Concentrations of 25-Hydroxyvitamin D. The Journal of Clinical Endocrinology & Metabolism (The Endocrine Society). 2008, 93 (3): 677–681. ISSN 0021-972X. doi:10.1210/jc.2007-2308.  Rachael M. Biancuzzo, Azzie Young, Douglass Bibuld, Mona H. Cai, Michael R. Winter, Ellen K. Klein, Allen Ameri, Richard Reitz, Wael Salameh, Tai C. Chen, Michael F. Holick. Fortification of orange juice with vitamin D(2) or vitamin D(3) is as effective as an oral supplement in maintaining vitamin D status in adults. The American Journal of Clinical Nutrition. 2010-06, 91 (6): 1621–1626 [2019-02-12]. ISSN 1938-3207. PMC 2869510 . PMID 20427729. doi:10.3945/ajcn.2009.27972. （原始内容存档于2020-04-25）.  Tripkovic, L; Lambert, H; Hart, K; Smith, CP; Bucca, G; Penson, S; Chope, G; Hyppönen, E; Berry, J; Vieth, R; Lanham-New, S. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis.. The American Journal of Clinical Nutrition. June 2012, 95 (6): 1357–64. PMC 3349454 . PMID 22552031. doi:10.3945/ajcn.111.031070.  Biancuzzo RM, Clarke N, Reitz RE, Travison TG, Holick MF. Serum concentrations of 1,25-dihydroxyvitamin D2 and 1,25-dihydroxyvitamin D3 in response to vitamin D2 and vitamin D3 supplementation. The Journal of Clinical Endocrinology and Metabolism. March 2013, 98 (3): 973–9. PMC 3590486 . PMID 23386645. doi:10.1210/jc.2012-2114.  Borel P, Caillaud D, Cano NJ. Vitamin D bioavailability: state of the art. Critical Reviews in Food Science and Nutrition. 2015, 55 (9): 1193–205. PMID 24915331. doi:10.1080/10408398.2012.688897.  Shah, Iltaf; Petroczi, Andrea; Tabet, Naji; Klugman, Anthony; Isaac, Mokhtar; P. Naughton, Declan. Low 25OH Vitamin D2 Levels Found in Untreated Alzheimer’s Patients, Compared to Acetylcholinesterase-Inhibitor Treated and Controls. Current Alzheimer Research (Bentham Science Publishers Ltd.). 2012-10-01, 9 (9): 1069–1076. ISSN 1567-2050. doi:10.2174/156720512803568975.  Suda, T; DeLuca, HF; Schnoes, H; Blunt, JW. 25-hydroxyergocalciferol: a biologically active metabolite of vitamin D2.. Biochemical and biophysical research communications. 1969-04-29, 35 (2): 182–5. PMID 5305760.  IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN): Nomenclature of vitamin D. Recommendations 1981.. European journal of biochemistry. 1982-05-17, 124 (2): 223–7. PMID 7094913. doi:10.1111/j.1432-1033.1982.tb06581.x.  Bikle, DD. Vitamin D metabolism, mechanism of action, and clinical applications.. Chemistry & biology. 2014-03-20, 21 (3): 319–29. PMC 3968073 . PMID 24529992. doi:10.1016/j.chembiol.2013.12.016.  Houghton, LA; Vieth, R. The case against ergocalciferol (vitamin D2) as a vitamin supplement.. The American journal of clinical nutrition. October 2006, 84 (4): 694–7. PMID 17023693. doi:10.1093/ajcn/84.4.694.  Wang, Ting; Bengtsson, Göran; Kärnefelt, Ingvar; Björn, Lars Olof. Provitamins and vitamins D2 and D3 in Cladina spp. over a latitudinal gradient: possible correlation with UV levels. Journal of Photochemistry and Photobiology B: Biology (Elsevier BV). 2001, 62 (1-2): 118–122. ISSN 1011-1344. PMID 11693362. doi:10.1016/s1011-1344(01)00160-9.  USDA nutrient database – use the keyword 'portabella' and then click submit. [2015-02-19]. （原始内容存档于2015-02-22）.  Dr. Duke's Phytochemical and Ethnobotanical Databases. [2015-02-19]. （原始内容存档于2015-10-16）.  Haytowitz DB. Vitamin D in mushrooms (PDF). Nutrient Data Laboratory, US Department of Agriculture. 2009 [2018-04-16]. （原始内容存档 (PDF)于2021-02-01）.  Simon, R. R.; Borzelleca, J. F.; Deluca, H. F.; Weaver, C. M. Safety assessment of the post-harvest treatment of button mushrooms (Agaricus bisporus) using ultraviolet light. Food and Chemical Toxicology. 2013, 56: 278–89. PMID 23485617. doi:10.1016/j.fct.2013.02.009.  Hohman, E. E.; Martin, B. R.; Lachcik, P. J.; Gordon, D. T.; Fleet, J. C.; Weaver, C. M. Bioavailability and Efficacy of Vitamin D2from UV-Irradiated Yeast in Growing, Vitamin D-Deficient Rats. Journal of Agricultural and Food Chemistry. 2011, 59 (6): 2341–2346. PMC 3235799 . PMID 21332187. doi:10.1021/jf104679c.  P Urbain; F Singler; G Ihorst; H-K Biesalski; H Bertz. Bioavailability of vitamin D2 from UV-B-irradiated button mushrooms in healthy adults deficient in serum 25-hydroxyvitamin D: a randomized controlled trial. European Journal of Clinical Nutrition. August 2011, 65 (8): 965–971 [2018-04-09]. PMID 21540874. doi:10.1038/ejcn.2011.53. （原始内容存档于2016-02-03）.  Koyyalamudi, SR; Jeong, SC; Song, CH; Cho, KY; Pang, G. Vitamin D2 formation and bioavailability from Agaricus bisporus button mushrooms treated with ultraviolet irradiation. J Agric Food Chem. 2009, 57 (8): 3351–5. PMID 19281276. doi:10.1021/jf803908q.  Bringing Mushrooms Out of the Dark. MSNBC. 2006-04-18 [2007-08-06]. （原始内容存档于2007-11-01）.  Holick MF. The vitamin D epidemic and its health consequences (PDF). The Journal of Nutrition. November 2005, 135 (11): 2739S–48S [2018-04-21]. PMID 16251641. （原始内容存档 (PDF)于2017-11-18）. [Vitamin D3] is produced commercially by extracting 7-dehydrocholesterol from wool fat, followed by UVB irradiation and purification [...] [Vitamin D2] is commercially made by irradiating and then purifying the ergosterol extracted from yeast