Evidence That 1,25-Dihydroxyvitamin D3 Is the Physiologically Active Metabolite of Vitamin D3*

摘要: I. Introduction THE REALIZATION in the mid-1960s that vitamin D3 is metabolized led to an extensive effort by several laboratories identify metabolites produced and determine their biological activities. The identification of 1,25-dihydroxyvitamin [1,25-(OH)2D3] as most potent rapidly acting metabolite stimulating intestinal absorption calcium mobilization bone mineral suggested this compound physiologically active hormonal form vitamin. Subsequent studies showing rapid turnover 1,25-(OH)2D3, presence a specific 1,25-(OH)2D3 receptor target tissues, intricate regulation renal 25-hydroxyvitamin (25-OHD3)-1-hydroxylase all supported theory. However, late 1970s possibility additional have actions distinct from those particularly on skeletal mineralization embryonic chick development, was groups. Particular attent...