Estriol (Oestriol) is a hydroxylated metabolite of ESTRADIOL or ESTRONE that has a hydroxyl group at C3, 16-alpha, and 17-beta position. Estriol is a major urinary estrogen. During PREGNANCY, a large amount of estriol is produced by the PLACENTA.

腹腔注射20 mg/kg Estriol处理大鼠,通过依赖于由大鼠肠道通透性增加引起的门静脉血内毒素升高引起的CD14增加的机制,使Kupffer细胞对脂多糖敏感;而在注射亚致死剂量的LPS（5 mg/kg）之前24小时腹膜内给予Estriol的一半大鼠在24小时内死亡.在mPTEN +/-小鼠中,Estriol处理导致子宫湿重与体重的相对比例增加187.54％,在野生型小鼠中Estriol使该比例也增加到176.88％.

研究表明,雌激素（雌酮,雌二醇和雌三醇）抑制阿尔茨海默病相关的低级Aβ寡聚体形成,其中雌三醇显示出最强的体外活性。无细胞转录试验表明,雌三醇所表现的抗雌激素活性是由于干扰雌二醇诱导的阳性协同结合和受体二聚化,hER复合物与ERE的结合以及减少雌二醇依赖性转录,这种作用存在剂量依赖性。使用G-1的MTT分析显示,在SkBr3细胞中,在作为GPR30依赖性途径拮抗剂的1 μM雌三醇存在下,100 nM G-1诱导的增殖作用被消除。

For the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cells are cultured in plastic 96-well plates under 200 μL of growth medium and at an initial density of 10,000 cells per well. Cells are washed once they have attached and further incubated in medium containing 2.5% charcoal-stripped FBS with the indicated treatment. The medium is changed every 2 days (with treatment). Where applicable, 200 ng of the indicated plasmids are transfected every 2 days before treatments using Fugene6 Reagent, as recommended by the manufacturer. Following 6 days of incubation, the assay mixture (10μL per well) containing 1 mg/mL 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) is added to each well and incubated at 37 ?C for 4 h in a 5% CO2 atmosphere. The yellow tetrazolium MTT, reduced by metabolically active cells, results in intracellular purple formazan, which is released after overnight incubation with 200 μL 1% sodium dodecyl sulfate in 0.01N HCL and quantified spectrophotometrically by reading absorbance at 570 nM using an enzyme-linked immunosorbent assay plate reader.(Only for Reference)