Calcitriol (1,25-Dihydroxyvitamin D3) is a metabolite of vitamin D and a vitamin D receptor (VDR) agonist (IC50=0.4 nM). Calcitriol increases intestinal absorption of calcium and phosphorus, and increases bone resorption with parathyroid hormone.

方法：恶性胸膜间皮瘤细胞 MSTO-211H、REN 和间皮细胞 MeT-5A 用 Calcitriol (1-100 nM) 处理 24 h，使用 MTT Assay 检测细胞活力。
结果：Calcitriol 处理导致 MSTO-211H 和 REN 细胞的生存能力剂量依赖性降低。用 Calcitriol 处理的非恶性 MeT-5A 间皮细胞的活力没有变化。[1]
方法：人结直肠癌细胞 HT29 和 SW480 用 Calcitriol (100 nM) 处理 48 h，使用 Western Blot 检测靶点蛋白表达水平。
结果：Calcitriol 增加了细胞中 E-cadherin 的表达。Calcitriol 还降低了 cyclin D1 和 c-Myc 的表达，这两个基因是 HT29 和 SW480 细胞中 Wnt/β-catenin 信号传导的两个下游靶基因。[2]

方法：为研究对急性肺损伤的作用，将 Calcitriol (1.0 µg/kg) 腹腔注射给 CD-1 小鼠，1-48 h 后注射 LPS (1.0 mg/kg)。
结果：Calcitriol 明显减轻了 LPS 诱导的肺部炎症细胞浸润，以及血清和肺匀浆中 TNF-α 和 MIP-2 的升高。[3]
方法：为研究对动脉粥样硬化的作用，将 Calcitriol (20-200 ng/mouse in carboxymethylcellulose) 灌胃给药给 ApoE-/- 小鼠，每周两次，持续十二周。
结果：口服 Calcitriol 可减少主动脉窦的动脉粥样硬化病变、巨噬细胞积聚和 CD4(+)T 细胞浸润。Calcitriol 治疗的小鼠中，肠系膜淋巴结、脾脏和动脉粥样硬化病变中 Foxp3(+) 调节性 T 细胞显著增加，CD80(+)CD86(+)DC) 减少，同时 IL-10 和 IL-12 mRNA 表达增加。[4]

Calcitriol is dissolved in DMSO and stored, and then diluted with appropriate medium before use[1]. Experiments are performed using parathyroid tissue slices instead of dispersed parathyroid cells so that tissue architecture is maintained. Parathyroid glands are cut into small pieces of approximately 1 mm3 and placed in individual wells (24 well dishes) with constant shaking at 37°C and placed in an incubator with a humid atmosphere. The incubation medium is buffered (pH 7.4) and contained 125 mM NaCl, 5.9 mM KCl, 0.5 mM MgCl2, 1 mM NaH2PO4, and Na2HPO4 (1:2 ratio), 1 mM Na-pyruvate, 4 mM glutamine, 12 mM glucose, and 25 mM HEPES. Insulin 0.1 IU/mL, bovine serum albumin 0.1%, penicillin G 100 IU/mL, and streptomycin 100 μg/mL are added to the medium. CaCl2 is added to achieve a final target ionized calcium concentration of 1.25 mM as measured with a selective electrode (634 Ca/pH analyzer). Ionized calcium concentration is also measured in each well after the completion of the experiment, and no change in the ionized calcium concentration is observed. Calcitriol is added to the medium to achieve concentrations ranging from 10-10 to 10-7 M. To quantify the amount of free Calcitriol, we filtered the medium through a membrane with a 5000-MW cutoff and Calcitriol is measured by RIA (Gamma 1,25-Dihydroxyvitamin D). As compared with total Calcitriol, the concentration of free Calcitriol is decreased by one order of magnitude[1].