Stoica G, Koestner A, Capen C C
Am J Pathol. 1983 Feb;110(2):161-9.
A single intraperitoneal inoculation of 180 mg/kg N-ethyl-N-nitrosourea (ENU) into 30-day-old outbred Sprague-Dawley (CD) rats resulted in an 90% incidence of mammary tumors (MTs) after an average latent period of 93 days, with an 85% rate of malignancy. The incidence, induction period, number of tumors per rats, and the rate of malignancy were reduced in rats ovariectomized prior to or shortly after (5 days) ENU exposure. Over 70% of the ENU-induced MTs regressed following ovarioectomy. The malignant MTs developed from nodules located in the terminal end buds (TEB), which are believed to contain the most susceptible cell population for chemical carcinogens. The serum calcium was elevated above control values in 92% of intact rats evaluated with MTs in the absence of bone metastases. No correlation was demonstrated between the volume of MTs or total number of MTs and the serum calcium level. The ENU-induced MT is a reproducible animal model that can be used in the investigation of the early changes in mammary cells (especially TEB) and the interrelationships between the carcinogen and ovarian hormones associated with neoplastic transformation.
对30日龄的远交群斯普拉格-道利（CD）大鼠进行单次腹腔注射180毫克/千克的N-乙基-N-亚硝基脲（ENU），平均潜伏期93天后，乳腺肿瘤（MTs）的发病率为90%，恶性率为85%。在ENU暴露前或暴露后不久（5天）进行卵巢切除的大鼠中，MTs的发病率、诱导期、每只大鼠的肿瘤数量以及恶性率均有所降低。超过70%的ENU诱导的MTs在卵巢切除后消退。恶性MTs由位于终末芽（TEB）的结节发展而来，据信TEB包含对化学致癌物最敏感的细胞群体。在没有骨转移的情况下，92%患有MTs的完整大鼠血清钙升高至对照值以上。MTs的体积或MTs总数与血清钙水平之间未显示出相关性。ENU诱导的MT是一种可重复的动物模型，可用于研究乳腺细胞（尤其是TEB）的早期变化以及致癌物与卵巢激素之间与肿瘤转化相关的相互关系。
