title: Effects of neonatally administered low-dose diethylstilbestrol on the induction of mammary carcinomas and dysplasias induced by 7,12-dimethylbenz [a] anthracene in female rats.
abstract: The aim of this study was to investigate the effects of neonatal administration of diethylstilbestrol (DES) on the induction of mammary carcinomas (MCs) and dysplasias (MDs) induced by 7,12-dimethylbenz[a]anthracene (DMBA) in female rats. Three different methods of continuous administration of DES (1 microg) were used: 0-14, 0-5 and 6-14 days after birth, and all rats were given DMBA (10 mg) at 50 days after birth. All rats administered DES showed persistent estrus and anovulatory ovaries. In rats administered DES from 0-14 days after birth, neither MCs nor MDs were observed, and serum levels of both estrogen and progesterone were significantly lower than in controls at 100 days after birth. In rats administered DES from 0-5 days after birth, the incidence and number of MCs were significantly lower while the number ofMDs was slightly higher than in controls. In rats administered DES from 6-14 days after birth, the incidence of MCs was equal to that of the controls while the incidence and number ofMDs were significantly higher. These results suggest that neonatal periods of exposure and doses of endocrine disruptors, such as DES, could affect the incidence and progression of MCs and MDs.
authors.affiliation: Department of Tumor Pathology, Field of Oncology, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Umekita
authors.forename: Masakazu
authors.initials: M
authors.lastname: Souda
authors.forename: Kentaro
authors.initials: K
authors.lastname: Gejima
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawashima
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Nagata
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yoshida
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity*; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens / Q000633:toxicity*; D004054:Diethylstilbestrol / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology*; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002273:Carcinogens; D015127:9,10-Dimethyl-1,2-benzanthracene; D004054:Diethylstilbestrol