diethylnitrosamine-initiated and 0.85 % nacl solution-treated noninitiated female sprague-dawley rats were transferred to semisynthetic diets containing mestranol ( 0 , 0.1 , or 0.5 ppm ) , ethinyl estradiol ( 0.5 ppm ) , estradiol ( 0.6 ppm ) , or mestranol plus beta-methasone ( 0.5 and 0.2 ppm , respectively ) .
C0015011
ethinyl estradiol
C0025506
mestranol