前立腺腫瘍の実験的研究 II: 実験的前立腺腫瘍発生に及ぼす性ホルモンの影響

Abstract

As it was described in the Part I of the article, experi m ental studies were carried out on the effects of male and female sexual hormones and castration to the development of prostatic tumors following administration of 20-MCT in wistar strain rats. 1. Duration till the initial development. The earliest development of the tumor, being 74 days, was observed in the group given female sexual hormone. The castrated animals showed a longer latency, 80 days. A tendency of delay, as 95 days, was seen in the group given male sexual hormone. 2. Incidence. The incidences of the tumor through out the experiment in the each group treated with male sexual hormone, female sexual hormone and castration were 60.0% (15 out of 25 animals), 87.5% (22 out of 25) and 59.2% (14 out of 25) respectively. In the group given mal e sexual hormone, although a delay in the initial development of tumor and a low incidence were observed, a rapid increase in the incidence was seen after .6 month period, being 71.3% (10 out of 14). A similar tendency was also demonstrated in the group of castration, being 68.5% (13 out of 19). However, in the group treated with female sexual hormone, 100 per cent occurrence of tumor was demonstrated from the earlier period of the study and a decrease in the incidence was seen after 6 months, being 85% (17 out of 20). 3. Histological findings. No specific histo l o gical finding depending upon the sexual hormones given was demonstrated, and the majority of them showed squamous epithelial type in generally. With administration of male sexual hormone, development of cellular foci of relatively large squamous epitheliar cells as well as frequent occurrence of papilloma were demonstrated. In the group given female sexual hormone, the tumors, which are larger than that of in the other groups, showed marked evidence of undifferentiation with severe infiltration and vigorously active proliferation. In the castrated group marked proliferation of the interstitial tissue with small cancer nestles within the proliferative area were demonstrated. 4. Metastasis and complications. As described in th e Part I, metastasis was found in the regional lymphnodes and the neighboring accessory sexual organs complications such as infections and urinary passage disturbances were encountered. These results of the experimental studies which are showing that, in combinating administration of 20-MCT and sexual hormones, development of prostatic tumor is accelerated by environmental effect of the high female sexual hormone, indicate that development of prostatic cancer is not necessary to depend only upon male sexual hormone, but female sexual hormone is supposed to be an important factor for the prostatic carcinogenesis despite the functional mechanism is not able to clarify. It is postulated that the both sexual hormones are concerned with development of prostatic tumors through complicated pituitary-hypothalamic system.