Sequential Observation of Rat Prostate Lesion Development Induced by 3,2′‐Dimethyl‐4‐aminobiphenyl and Testosterone

Shirai, Tomoyuki; Imaida, Katsumi; Iwasaki, Shogo; Mori, Toshio; Tada, Minoru; Ito, Nobuyuki

doi:10.1111/j.1349-7006.1993.tb02778.x

Cited by 19 publications

(16 citation statements)

References 8 publications

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“…The incidences of the neoplastic lesions in the control diet group were comparable to those previously reported. 6,7,22) In the ventral prostate, no adenocarcinomas were found. In the dorso-lateral and anterior prostate, the isoflavone mixture supplement decreased the incidence of adenocarcinomas, but the differences were not statistically significant.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Effects of a Soybean Isoflavone Mixture on Carcinogenesis in Prostate and Seminal Vesicles of F344 Rats

Onozawa

Kawamori

Baba

et al. 1999

Japanese Journal of Cancer Research

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Section: Resultsmentioning

confidence: 99%

“…Rats were given AIN-76A basal diet (Dyets Inc., Bethlehem, PA) or basal diet containing 100 and 400 ppm soybean isoflavone mixture and water ad libitum. Experimental procedure The experiment was performed according to the protocol established by Shirai et al, 22) as shown in Fig. 1.…”

Section: Methodsmentioning

confidence: 99%

Effects of a Soybean Isoflavone Mixture on Carcinogenesis in Prostate and Seminal Vesicles of F344 Rats

Onozawa

Kawamori

Baba

et al. 1999

Japanese Journal of Cancer Research

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“…Various findings have eluciules and development of metastases. 22,23 In addition, dated that androgens are deeply involved in the proShirai et al showed that, although carcinogenesis in motion step, including the fact that prostate carcinothe ventral lobe is androgen-dependent, there is a mas shrink in size after castration 2 and the fact that strong possibility that carcinogenesis in the other porthe plasma testosterone level or 5-alpha reductase actions of the accessory sex organs has lost its androgentivity is significantly elevated in races showing a high dependence in the early phase in spite of the fact that incidence of prostate carcinoma. [18][19][20][21] promotion by TP is essential.…”

Section: Discussionmentioning

confidence: 97%

A five-alpha reductase inhibitor or an antiandrogen prevents the progression of microscopic prostate carcinoma to macroscopic carcinoma in rats

Tsukamoto

Akaza

Onozawa

et al. 1998

Cancer

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of 5-alpha reductase inhibitor (e.g., finasteride) and a pure antiandrogen (e.g., Hideyuki Akaza 1 casodex) on rat prostate carcinogenesis and to determine whether latent prostate Mizuki Onozawa 1 carcinoma can be prevented to develop to clinically significant cancer by use of Tomoyuki Shirai 2 these drugs. Yukitaka Ideyama 3 METHODS. F344 rats were subcutaneously administered 3,2-dimethyl-4-aminobi-phenyl (DMAB) for the first 20 weeks and testosterone propionate throughout the 1 Department of Urology, Institute of Clinical 60-week study. Finasteride (5 mg/kg and 15 mg/kg, 2 times per week) and casodex Medicine, University of Tsukuba, Tsukuba, Ibar-(15 mg/kg, 30 mg/kg, and 60 mg/kg, 3 times per week) were administered orally aki, Japan. during the last 40 weeks of the study. Tumors were classified as visible prostate 2 First Department of Pathology, Nagoya City carcinoma when they could be recognized with the naked eye and as microscopic University, Nagoya, Aichi, Japan. prostate carcinoma when detectable only with a microscope. 3 Endocrinology and Metabolic Disease Re-RESULTS. The incidence of visible prostate carcinoma was 51% (18 of 35 rats) in search Laboratory, Institute for Drug Discovery the positive control group, whereas it was 40% (4 of 10 rats) in the finasteride 5 Research, Yamanouchi Pharmaceutical Co., mg/kg group, 16.7% (2 of 12 rats, P Å 0.0091) in the finasteride 15 mg/kg group, Ltd., Tsukuba, Ibaraki, Japan. 20% (4 of 20 rats, P Å 0.05) in the casodex 15 mg/kg group, 14.3% (3 of 21 rats, P Å 0.0008) in the casodex 30 mg/kg group, and 0% (0 of 11 rats, P Å 0.0002) in the casodex 60 mg/kg group. On the other hand, when visible carcinomas and microscopic carcinomas were handled together, only casodex 60 mg/kg significantly inhibited the carcinogenesis rate. CONCLUSIONS. Finasteride achieved dose-dependent inhibition of macroscopic rat prostate carcinogenesis, and casodex also inhibited macroscopic prostate carcino-genesis. However, both drugs showed insufficient prevention of carcinogenesis at the microscopic level. These findings indicate that, in clinical medicine as well, such drugs may also be able to prevent the progression of latent prostate carcinoma to life-threatening disease.

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“…Shirai et al (1991) established an experimental animal model of prostate cancer by exposure to 3,2′-dimethyl-4-aminobiphenyl (DMAB) and testosterone propionate (TP). In this model, carcinomas were observed from week 40 and thereafter increased in a time-dependent fashion until week 60 (Shirai et al 1993(Shirai et al , 1994. However, Shirai (1995) reported that this model had androgenindependent properties, despite the promotion effects of testosterone.…”

Section: Introductionmentioning

confidence: 89%

Carcinogenesis in accessory sex organs of rats induced by 3,2′-dimethyl-4-aminobiphenyl: response to androgen deprivation

Tamura

Suzuki

et al. 1997

Histochemistry and Cell Biology

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It is generally accepted that early human prostate cancers reveal higher androgen dependency than do advanced ones. In the present study, we examined whether the animal model of prostate cancer has already lost androgen dependency at the early stages of carcinogenesis. At experimental week 46, androgen deprivation was induced in rats and the incidences of atypical hyperplasia and cancer were examined in the ventral, dorsolateral prostate, coagulating glands, and seminal vesicles. Androgen deprivation significantly lowered the incidence of atypical hyperplasia in all four organs. As for the incidence of cancer, no significant differences were observed in the coagulating glands and seminal vesicles. Regarding atypical hyperplasia, androgen deprivation significantly decreased the proliferative cell nuclear antigen labeling index in the coagulating gland and seminal vesicles. The presence of cancer was also decreased in the coagulating gland but not in the seminal vesicles. With control group specimens, more intense staining of androgen receptor was observed in atypical hyperplasias than in cancers. Compared with the atypical hyperplasias, the cancers revealed low androgen dependency at the early stages of carcinogenesis. The cancers in the seminal vesicles also revealed higher androgen independency than did those in the coagulating gland.

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Sequential Observation of Rat Prostate Lesion Development Induced by 3,2′‐Dimethyl‐4‐aminobiphenyl and Testosterone

Cited by 19 publications

References 8 publications

Effects of a Soybean Isoflavone Mixture on Carcinogenesis in Prostate and Seminal Vesicles of F344 Rats

Effects of a Soybean Isoflavone Mixture on Carcinogenesis in Prostate and Seminal Vesicles of F344 Rats

A five-alpha reductase inhibitor or an antiandrogen prevents the progression of microscopic prostate carcinoma to macroscopic carcinoma in rats

Carcinogenesis in accessory sex organs of rats induced by 3,2′-dimethyl-4-aminobiphenyl: response to androgen deprivation

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