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1维生素D与钙的代谢和作用维生素D通过改变肠道钙的吸收率,调节血钙浓度。1,25-二羟维生素D[1,25-(OH)2D]与小肠维生素D受体结合后,可增加小肠黏膜对钙的通透性,并诱导钙转运蛋白产生,促进钙、磷在肠道内主动转运吸收过程。1,25-(OH)2D处于正常水平的情况下,低钙饮食时肠钙吸收率可达75%,而高钙饮食时肠钙吸收率为50%。当1,25-(OH)2D低于正常水平时,肠钙吸收率仅为7%[2]。
1 vitamin D and calcium metabolism and role of vitamin D by changing the intestinal absorption of calcium, regulating blood calcium concentration. 1,25-dihydroxyvitamin D [1,25- (OH) 2D] binds to the small intestine vitamin D receptor to increase the permeability of small intestinal mucosa to calcium and induce the production of calcium transporter and promote the accumulation of calcium and phosphorus in the Intestinal transport initiative absorption process. At normal dietary levels of 1,25- (OH) 2D, intestinal calcium uptake was 75% in the low-calcium diet and 50% in the high-calcium diet. When 1,25- (OH) 2D is lower than normal levels, intestinal calcium absorption rate of only 7% [2].