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一、维生素D及其受体(一)维生素D的来源及代谢维生素D主要来源于紫外线照射后皮肤中合成及食物摄取。维生素D在小肠吸收,经淋巴循环入血,循环至肝脏后,经25-羟化酶(由CYP2R1编码)作用变成25(OH)D。25(OH)D是循环中维生素D的主要形式,并认为是反映血清维生素D水平的可靠指标。25(OH)D再经肾脏1-α羟化酶(由CYP27B1编码)的作用生成有生物活性的代谢物1,25(OH)_2D_3,与外周靶细胞的维生素D受体结合,发挥多种生物活性作用。24-羟化酶(由CYP24A1编码)可使循环中各种
First, vitamin D and its receptors (A) the source of vitamin D and metabolism Vitamin D is mainly derived from the skin after ultraviolet radiation synthesis and food intake. Vitamin D is absorbed in the small intestine and enters the blood through the lymphatic circulation. After circulating to the liver, it becomes 25 (OH) D via 25-hydroxylase (encoded by CYP2R1). 25 (OH) D is the major form of circulating vitamin D and is considered as a reliable indicator of serum vitamin D levels. 25 (OH) D, which is produced by the action of renal 1-α-hydroxylase (encoded by CYP27B1), produces biologically active metabolite 1,25 (OH) _2D_3 and binds to the vitamin D receptor of peripheral target cells to exert its effects Biological activity. 24-hydroxylase (encoded by CYP24A1) can make a variety of cycles