Abstract
Six‐week‐old rats which had been orchiectomized at birth were given 3,2′‐dimethyl‐4‐aminobiphenyl (DMAB) at various doses combined with a stimulus to prostate epithelial cell proliferation in the form of oral administration of methyltestosterone (MT) for 4 weeks. Thereafter MT treatment was continued or the animals received subcutaneous implants of testosterone propionate (TP) and were maintained until sacrifice at week 60. Although prostatitis and prostatic enlargement were frequently observed, especially in the TP group, numbers of atypical hyperplastic lesions were low and only one prostatic carcinoma in situ developed. Thus, despite the presence of proliferation, castration brought about a significant reduction in susceptibility to DMAB.
Keywords: DMAB, Prostate, Carcinogenesis, Castration, Newborn rat
Full Text
The Full Text of this article is available as a PDF (194.7 KB).
References
- 1. ) Bosland , M. C. , Prinsen , M. K. and Kroes , R.Adenocarcinomas of the prostate induced by N‐nitroso‐N‐methylurea in rats pretreated with cyproterone acetate and testosterone . Cancer Lett. , 18 , 69 – 78 ( 1983. ). [DOI] [PubMed] [Google Scholar]
- 2. ) Shirai , T. , Fukushima , S. , Ikawa , E. , Tagawa , Y. and Ito , N.Induction of prostate carcinoma in situ at high incidence in F344 rats by a combination of 3,2′‐dimethyl‐4 ‐ aminobiphenyl and ethinyl estradiol . Cancer Res. , 46 , 6423 – 6426 ( 1986. ). [PubMed] [Google Scholar]
- 3. ) Ito , N. , Shirai , T. , Tagawa , Y. , Nakamura , A. and Fukushima , S.Variation in tumor yield in the prostate and other organs of the rat in response to varied dosage and duration of administration of 3,2′ ‐ dimethyl ‐ 4‐ aminobiphenyl . Cancer Res. , 48 , 4629 – 4632 ( 1988. ). [PubMed] [Google Scholar]
- 4. ) Pour , P. M. and Stepan , K.Induction of prostatic carcinomas and lower urinary tract neoplasms by combined treatment of intact and castrated rats with testosterone propionate and N‐nitrosobis(2‐oxopropyl)amine . Cancer Res. , 47 , 5699 – 5706 ( 1987. ). [PubMed] [Google Scholar]
- 5. ) Shirai , T. , Tagawa , Y. , Fukushima , S. , Asamoto , M. and Ito , N.Lack of tumorigenic response in the prostate gland of castrated F344 rats by 3,2′‐ dimethyl ‐ 4‐aminobiphenyl given with methyltestosterone . Cancer Lett. , 35 , 1 – 6 ( 1987. ). [DOI] [PubMed] [Google Scholar]
- 6. ) Chung , L. W. K. and Ferland‐Raymond , G.Differences among rat sex accessory glands in their neonatal androgen dependency . Endocrinology , 97 , 145 – 153 ( 1975. ). [DOI] [PubMed] [Google Scholar]
- 7. ) Chung , L. W. K. and MacFadden , D. K.Sex steroids imprinting and prostatic growth . Invest. Urol. , 337 – 342 ( 1980. ). [PubMed] [Google Scholar]
- 8. ) Katayama , S. , Fiala , E. , Reddy , B. S. , Rivenson , A. , Silverman , J. , Williams , G. and Weisburger , J. H.Prostate adenocarcinoma in rats: induction by 3,2′‐dimethyl‐4‐aminobiphenyl . J. Natl. Cancer Inst. , 68 , 867 – 873 ( 1982. ). [PubMed] [Google Scholar]