[A hormonal impact on DMBA-induced rat ovarian cancer--detection of estrogen receptors, and resultant morphologic changes after estrogen application].

Hormonal dependencies of 7,12 dimethylbenz (a) anthracene (DMBA)-induced rat ovarian cancer were studied. To reveal intratumoral estrogen receptors, dextran coated charcoal (D.C.C.) methods were utilized. In order to change the hormonal level in the rat during the period of tumor induction, serial weekly administrations of estrogen were performed from 5 to 20 weeks after the application of DMBA. Resultant morphologic changes in the induced tumor after the hormonal impacts were observed by light and electron microscope and the results obtained were as follows; 1) Estrogen receptor existed in 80% of the rat ovarian cancers induced by DMBA 2) In the estrogen injected group, a higher incidence and larger growth of the induced tumor were observed than in the hormonally non-treated group 3) A major difference between the histologic features of estrogen group and non-treated group was that the ovarian adenocarcinoma of the former, but not the latter, was associated with a significant proliferation of connected tissues and contained many signet ring cells involving intracytoplasmic canaliculi 4) Ultrastructural findings of these cells were characterized by well developed microvilli, mitochondria, golgi complexes and abundant lipid droplets 5) The proliferation of the DMBA-induced cancer cells in culture was promoted by 17 beta-estradiol application, suggesting its hormonal dependence.