25,26-Dihydroxyvitamin D3(25,26-dihydroxycholecalciferol) is a metabolite of vitamin D3 with intestinal calcium transport activity.IC50 value:Target: VD metaboliteThe biological activity of synthetic 24,25 and 25,26 diOHD3 was studied in vitamin D-deficient rats. The purpose of this study was to investigate the influence of small doses of both metabolites (0.125-0.250 mug) upon intestinal calcium transport and bone calcium mobilization. Both metabolites were able to increase calcium absorption in rats maintained on a calcium-deficient diet, but failed to do it in rats on a normal calcium diet. Bilateral nephrectomy suppressed this effect. The "bone calcium mobilization" of both derivatives was measured in vitamin D and calcium- or phosphorus-deprived rats after one intravenous dose. When serum calcium was initially low, 24,25 and 25,26 diOHD3 increased serum calcium moderately, but the increment was only significant with 24,25 diOHD3. Human Endogenous Metabolite

[1]. DeLuca HF, et al. 25,26-dihydroxycholecalciferol, a metabolite of vitamin D3 with intestinal calcium transport activity. Biochemistry. 1970 Nov 24;9(24):4776-80. [2]. Miravet L, et al. The biological activity of synthetic 25,26-dihydroxycholecalciferol and 24,25-dihydroxycholecalciferol in vitamin D-deficient rats. Calcif Tissue Res. 1976 Dec 2;21(3):145-52. [3]. Fraher LJ, et al. Determination of circulating 25,26-dihydroxycholecalciferol in man by radioimmunoassay. Clin Sci (Lond). 1980 Oct;59(4):257-63.