[GANN, 58, 253-266; June, 1967] UDC 616-006-021.6[618.11]:547.674 EXPERIMENTAL INDUCTION OF OVARIAN TUMORS IN MICE TREATED WITH SINGLE ADMINISTRATION OF 7,12- DIMETHYLBENZ[a]ANTHRACENE, AND ITS HISTOPATHOLOGICAL OBSERVATION (Plates XXXVII-XLI)

1) Induction of ovarian tumor with a single intragastric instillation of a large but tolerable doses of 7,12-dimethylbenz[a]anthracene (DMBA) was investigated on young female mice of C3H and C57BL strains, rats of Sprague-Dawley strain, guinea pigs, and rabbits. The ovarian tumor occurred in a high incidence only in C3H mice. 2) The induction of ovarian tumor in C3H mice with DMBA by various routes of administration such as intragastric instillation, intraperitoneal or intravenous injection was studied. The following tumor incidences were obtained in the treated mice: Single feeding, 59% until 7th month; intraperitoneal injection, 36% until 4th month; single intravenous injection, variable percentages at each month and average 57% after 6 months. Intraperitoneal injection of DMBA induced ovarian tumor earlier and in higher incidence than by other two routes but mortality of mice was unfortunately very high. 3) Histological observations revealed no normal ovaries in C3H mice given DMBA intravenously. Follicular structures were destroyed and oocytes vanished within one month. Proliferation of granulosa cell following its earlier non-specific pathological change progressed from microscopical nodule to a sizable gross tumor. These tumors were all granulosa-celled type. 4) Granulosa cell tumor arose probably from surviving granulosa cells in the partially degenerated follicles and its growth was stimulated by pituitary gland but there was still a probability that granulosa cell tumor might have originated from theca cells. 5) Frequent study of vaginal smears demonstrated possible association between the presence of tumor and estrogen activity.