维生素D代谢:当前状态。
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维生素D代谢:当前状态。
是中国减轻。1976年11月,29 (11):1258 - 70。
- PubMed ID
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187053年(在PubMed]
- 文摘
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已经有很大进步在我们对维生素d代谢的理解,现在清楚的是,维生素D3可以产生的皮肤或饮食中摄取。它迅速积累在肝脏进行25-hydroxylation,收益率25-OH-D3,维生素的主要循环代谢物。25-OH-D3继续肾脏经历两个羟基化。如果有一个生物需要钙或磷酸刺激肾脏25-OH-D3转换为1,25 (OH) 2-D3,钙和磷酸盐动员激素。然而,如果动物有足够的钙和磷的供应,l-hydroxylase关闭,而是25-OH-D3转换为24,25 - (OH) 2 d3。24岁的角色25 - (OH) 2 d3仍然未知;它可能是一个中间的inactivation-excretion机制。1,25 (OH) 2 d3所得的肠,刺激肠道运输和肠钙磷酸盐运输。它还能刺激骨钙动员和其他可能影响没有被发现在肌肉等组织。25-OH-D3-l-hydroxylase,位于线粒体只在肾,已被证明是一个三个组件系统涉及黄素蛋白,一种iron-sulfur蛋白质(肾铁氧还蛋白)和细胞色素p - 450。 This system has been successfully solubilized, the components isolated, and reconstituted. The 24-hydroxylase, however, has not yet been thoroughly studied. 1,25-(OH)2D3 is necessary for the appearance of the 24-hydroxylase; parathyroid hormone represses 24-hydroxylation. It is possible that the 24-hydroxylase represents the major regulated enzyme, so that its presence or absence may determine whether 1,25-(OH)2D3 is produced. Two metabolic pathways for 1,25-(OH)2D3 are known, conversion by the 24-hydroxylase to 1,24,25-(OH)3D3, and conversion of 1,25-(OH)2D3 to an unknown substance. In the latter instance, there occurs loss of a side chain piece, including at least one of the 26 and 27 carbons. Whether 1,25-(OH)2D3 must be metabolized further before it carries out all of its functions has yet to be established. The primary excretion route of vitamin D3 is via the bile into the feces. Urinary excretion appears small in magnitude and no excretion products have yet been identified positively. Much remains to be learned concerning the metabolism and function of vitamin D and its metabolites. This should therefore, prove to be a fruitful area of investigation for many years to come, especially since 1,25-(OH)2D3, 25-OH-D3, and lalpha-OH-D3 have been shown to be effective in a number of metabolic bone disease states.
DrugBank数据引用了这篇文章
- 药物
- 药物酶
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药物 酶 类 生物 药理作用 行动 维生素D 人体内25 -羟维生素d 1α羟化酶、线粒体 蛋白质 人类 是的底物细节 维生素D 维生素D 25-hydroxylase 蛋白质 人类 是的底物细节 - 药物反应
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反应 细节 细节 细节 细节
