title: Proliferative response of rat accessory sex organs to dietary sex hormones after castration or initial dietary administration of estrogen.
abstract: The hormone dependent proliferative response of five accessory sex organs was examined subsequent to castration-induced or estrogen-induced atrophy using male six-week-old F344 rats. Three weeks after castration, rats were treated with dietary methyltestosterone (300 ppm), ethinyl estradiol (0.75 ppm) or methyltestosterone plus ethinyl estradiol for up to 17 days. Cell proliferation was assessed by 3H-thymidine incorporation as determined from labelling indices using autoradiography. The maximum labelling indices which appeared on days 2 or 3 of administration of methyltestosterone were 24.3, 8.4, 9.6, 21.6 and 13.7% for the ventral, lateral and dorsal prostate, seminal vesicle and coagulating glands, respectively. Combined methyltestosterone and ethinyl estradiol induced mild proliferative responses whereas ethinyl estradiol did not. In a further group of non-castrated rats which were pretreated with dietary ethinyl estradiol for three weeks and then given methyltestosterone, the maximum labelling indices were about 70 to 80% of that in castrated rats.
mesh_terms: D000818:Animals; D002369:Castration; D002455:Cell Division / Q000187:drug effects; D004032:Diet; D004967:Estrogens / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D008297:Male; D008777:Methyltestosterone / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344; D012669:Seminal Vesicles / Q000187:drug effects*
chemical_list: D004967:Estrogens; D012739:Gonadal Steroid Hormones; D004997:Ethinyl Estradiol; D008777:Methyltestosterone