Effect of ovarian hormones on the induction of 1-methyl-1-nitrosourea-induced mammary cancer.
The concomitant administration of 20 micrograms 17 beta-estradiol and 4 mg progesterone/injection (5 days/week) over a 40-day treatment period beginning 10 days after methylnitrosourea (MNU) treatment was as effective as ovariectomy in inhibiting mammary cancers (an 84% reduction from non-hormone treated rats). The primary action of the hormones must have been directed at preneoplastic cells since the hormones were not given until 10 days after MNU (a direct-acting carcinogen with a short half-life).
D000818:Animals; D004347:Drug Interactions; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000517:prevention & control; D008770:Methylnitrosourea / Q000633:toxicity*; D009607:Nitrosourea Compounds / Q000633:toxicity*; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D009607:Nitrosourea Compounds; D011374:Progesterone; D004958:Estradiol; D008770:Methylnitrosourea