Effect of pharmacological doses of estrogen on ovary-independent rat mammary carcinoma containing estrogen and progesterone receptors.

Abstract

Mammary carcinoma induced in male Sprague-Dawley rats by multiple intragastric intubations of 7,12-dimethylbenz-(a)anthracene showed ovary-independent growth but contained estrogen receptors (ER) and progesterone receptors (Yoshida, Yoshida. Fukunishi, Sato, Okamoto, and Matsumoto, Cancer Res., 42: 2434-2439, 1982). Transplantable carcinoma (MT6) was obtained from dimethylbenz(a)anthracene-induced mammary carcinoma and then maintained in male rats. MT6 tumors with ER grew equally well in males, females, gonadectomized males, males given injections of bromocryptine (1 mg/day) or lisuride hydrogen maleate (50 micrograms/day), and gonadectomized males receiving smaller doses of 17 beta-estradiol (1 to 100 micrograms/2 days). However, the growth of MT6 was inhibited markedly by injection of a very large amount of 17 beta-estradiol (1 mg/2 days). Although transplanted MT6 tumors were ductal carcinoma with cribriform pattern with ER, tumors recurring after injection with 1 mg 17 beta-estradiol were found to be spindle cell carcinoma without ER, which could grow equally well in recipients treated with or without 1 mg 17 beta-estradiol. These observations suggest that the growth of ovary-independent MT6 tumors with ER and progesterone receptors is inhibited only by pharmacological doses of estrogens and that the loss of growth-inhibiting effect of pharmacological doses of estrogen of MT6 tumors occurs during high-dose estrogen treatment.

• Authors: H Yoshida, T Fukuhara, S Yamashi, A Yoshida, R Fukunishi, M Tsuji, K Matsumoto
• Journal: Cancer research (Cancer Res) Vol. 43 Issue 5 Pg. 2311-6 (May 1983) ISSN: 0008-5472 [Print] United States
• PMID: 6403234 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Estrogens
• Receptors, Estrogen
• Receptors, Progesterone
• Estradiol
• 9,10-Dimethyl-1,2-benzanthracene

Topics

• 9,10-Dimethyl-1,2-benzanthracene
• Animals
• Carcinoma (pathology)
• Castration
• Estradiol (pharmacology)
• Estrogens (pharmacology)
• Female
• Male
• Mammary Neoplasms, Experimental (chemically induced, metabolism, pathology)
• Neoplasm Transplantation
• Rats
• Rats, Inbred Strains
• Receptors, Estrogen (analysis)
• Receptors, Progesterone (analysis)
• Time Factors