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Published on: August 28, 2013
Effects of estrogen on growth of androgen-responsive rat prostatic tumor (R 3327)
Abstract:
It has been known that estrogen has synergistic effects with androgen on growth of normal male accessory sex organs of rats. The present study was therefore undertaken to examine the effects of estrogen on androgen-responsive rat Dunning R 3327 prostatic tumor. The weight of male accessory sex organs was suppressed by estrogen on growth of treatment, but synergistic effects of estrogen and androgen on these organs were seen following combined treatment with androgen and estrogen. In contrast to the effects of estrogen on accessory sex organs, estrogen influenced a R 3327 tumor only in the negative direction regardless of whether androgen was injected simultaneously or not. When the dihydrotestosterone injection was reduced from 500 to 100 micrograms/rat/day after the tumor appeared as subcutaneous nodules, the weight of the accessory sex organs was similar to that of the control animals. However, this amount of dihydrotestosterone increased tumor growth equally when compared to those treated with a pharmacological dose of dihydrotestosterone. Therefore, the response of R 3327 tumor to androgen was different from that of the accessory sex organs.
Insights
Estrogen suppresses growth of rat prostate tumors, unlike its synergistic effect on normal sex organs. This study highlights differential hormonal responses in prostate cancer versus healthy tissues.
Area of Science:
- Endocrinology
- Oncology
- Urology
Background:
- Estrogen exhibits synergistic effects with androgens on normal male accessory sex organs in rats.
- The Dunning R 3327 prostatic tumor is an androgen-responsive model system.
Purpose of the Study:
- To investigate the effects of estrogen on the androgen-responsive Dunning R 3327 rat prostatic tumor.
- To compare the influence of estrogen on tumor growth versus normal sex organ growth.
Main Methods:
- Administration of estrogen and/or dihydrotestosterone to rats bearing Dunning R 3327 tumors.
- Monitoring and measurement of accessory sex organ weights and tumor growth.
Main Results:
- Estrogen suppressed accessory sex organ growth but showed synergistic effects with androgen on these organs.
- Estrogen negatively impacted R 3327 tumor growth, irrespective of simultaneous androgen administration.
- Reduced dihydrotestosterone dosage still promoted tumor growth comparably to higher doses, indicating a distinct response compared to accessory sex organs.
Conclusions:
- The Dunning R 3327 prostatic tumor exhibits a different response to androgens than normal male accessory sex organs.
- Estrogen's effect on prostate tumor growth is inhibitory, contrasting with its role in normal sex organ development.
