ENU-Induced Ovarian Cancer

Carcinogenesis, in both humans and experimental animals, is recognized to represent a multistep process involving a sequence of morphophenotypical changes, which may lead to malignant transformation. Various in vivo and in vitro models were developed to better mechanistically understand specific aspects of carcinogenic process. N-Ethyl-N-nitrosourea (ENU) is recognized as a potent direct-acting neurocarcinogen in a variety of rat strains (1 ). One rat strain, Berlin Druckrey (BD-IV), has been observed to be relatively resistant to the development of neural tumors following transplacental administration of ENU (2 ,3 ). Few data have been reported on the effect of ENU in young BD-IV rats. It was reported that ENU administered intraperitoneally (i.p.) (90 mg/kg) to BD-IV 30-d-old female rats increased the incidence to up to 50% of an uncommon ovarian tumor with testicular characteristics (Sertoli cell tumor of the ovary) compared to controls (3%) (4 ). The ovarian tumors in BD-IV rats exceeded in incidence all other tumors encountered in this strain.