Preventive effects of Juzen-taiho-to on N-methyl-N-nitrosourea and estradiol-17 beta-induced endometrial carcinogenesis in mice

Two experiments were conducted to determine effects of Juzen-taiho-to on en dometrial carcinogenesis in mice. In the first experiment, Juzen-taiho-to t reatment (2 weeks) decreased the levels of estradiol-17 beta (E-2)-stimulat ed expression of c-fos/jun mRNA and their oncoproteins, determined by rever se transcription-polymerase chain reaction and Southern blot analysis, and the immunohistochemical method, in the uteri of ovarectomized mice. For the second experiment, 93 female ICR mice were given N-methyl-N-nitrosourea (M NU) solution (1 mg/100 g body weight) and normal saline (as controls) into their left and right uterine corpora, respectively, and were divided into f our groups. Group 1 was given a diet containing 0.2% Juzen-taiho-to and 5 p .p.m, E-2, Group 2 was given a diet containing 5 p,p,m, E-2 alone. Group 3 was given a diet containing 0.2% Juzen-taiho-to alone. Group 4 was kept on the basal diet alone and treated as a control. Juzen-taiho-to treatment sig nificantly decreased incidences of the uterine endometrial atypical (P < 0. 01), complex (P < 0.05) and simple hyperplasias (P < 0.01), under estrogeni c stimulation. It is suggested that Juzen-taiho-to has an inhibitory effect on E2-related endometrial carcinogenesis in mice, relevantly through suppr ession of estrogen-induced c-fos/jun-expression.