Marty M Sue, O'Connor John C
Toxicology & Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan.
Birth Defects Res B Dev Reprod Toxicol. 2014 Feb;101(1):63-79. doi: 10.1002/bdrb.21098. Epub 2014 Feb 10.
In 2009, companies began screening compounds using the US Environmental Protection Agency's Endocrine Disruptor Screening Program (EDSP). EDSP has two tiers: Tier 1 includes 11 assays to identify compounds with potential endocrine activity. This article describes two laboratories' experiences conducting Tier 1 uterotrophic and Hershberger assays. The uterotrophic assay detects estrogen receptor agonists through increases in uterine weight. The advantages of the uterotrophic rat models (immature vs. adult ovariectomized) and exposure routes are discussed. Across 29 studies, relative differences in uterine weights in the vehicle control group and 17α-ethynylestradiol-positive control group were reasonably reproducible. The Hershberger assay detects androgen receptor (AR) agonists, antagonists, and 5α-reductase inhibitors through changes in accessory sex tissue (AST) weights. Across 23 studies, AST weights were relatively reproducible for the vehicle groups (baseline), testosterone propionate (TP) groups (androgenic response), and flutamide + TP groups (antiandrogenic response). In one laboratory, one and four compounds were positive in the androgenic and antiandrogenic portions of the assay, respectively. Each compound was also positive for AR binding. In the other laboratory, three compounds showed potential antiandrogenic activity, but each compound was negative for AR binding and did not fit the profile for 5α-reductase inhibition. These compounds induced hepatic enzymes that enhanced testosterone metabolism/clearance, resulting in lower testosterone and decreased capacity to maintain AST weights. The Hershberger androgenic and antiandrogenic performance criteria were generally attainable. Overall, the uterotrophic and Hershberger assays were easily adopted and function as described for EDSP screening, although the mode of action for positive results may not be easily determined.
2009年，各公司开始使用美国环境保护局的内分泌干扰物筛选计划（EDSP）对化合物进行筛选。EDSP有两个层级：第一层包括11种检测方法，用于识别具有潜在内分泌活性的化合物。本文描述了两个实验室进行第一层子宫增重试验和赫什伯格试验的经验。子宫增重试验通过子宫重量增加来检测雌激素受体激动剂。讨论了子宫增重大鼠模型（未成熟与成年去卵巢）和暴露途径的优势。在29项研究中，载体对照组和17α-乙炔雌二醇阳性对照组子宫重量的相对差异具有合理的可重复性。赫什伯格试验通过附属生殖器官组织（AST）重量的变化来检测雄激素受体（AR）激动剂、拮抗剂和5α-还原酶抑制剂。在23项研究中，载体组（基线）、丙酸睾酮（TP）组（雄激素反应）和氟他胺+TP组（抗雄激素反应）的AST重量相对具有可重复性。在一个实验室中，分别有1种和4种化合物在试验的雄激素和抗雄激素部分呈阳性。每种化合物对AR结合也呈阳性。在另一个实验室中，有3种化合物显示出潜在的抗雄激素活性，但每种化合物对AR结合呈阴性，且不符合5α-还原酶抑制的特征。这些化合物诱导肝酶，增强睾酮代谢/清除，导致睾酮水平降低，并降低维持AST重量的能力。赫什伯格雄激素和抗雄激素性能标准通常是可以达到的。总体而言，子宫增重试验和赫什伯格试验很容易采用，并且如EDSP筛选所述发挥作用，尽管阳性结果的作用方式可能不容易确定。
