Abstract

The effects of estradiol-17β on androgen uptake, metabolism and binding were studied in rat epidymis in vivo in comparison with cyproterone acetate. Steroids (250 ug/100 g body weight) were injected 5 min prior to 3H-testosterone in castrate rats. Estradiol-17β inhibited 3H-testosterone uptake into epididymal cytosol by 58% as compared to 38% by cyproterone acetate. 3H-Testosterone uptake into epididymal nuclei was inhibited 95% by estradiol-17β and 83% by cyproterone acetate. Total bound radioactivity in cytosol fractions was reduced to a greater extent by estradiol-17β than cyproterone acetate when either 3H-testosterone or 3H-dihydrotestosterone was injected. Binding of 3H-dihydrotestosterone to nuclear receptors was completely abolished by estradiol-17β; whereas approximately 20% binding remained in the nuclear extract after cyproterone acetate treatment. Metabolism of 3H-testosterone in vivo was also altered by estradiol-17β, resulting in diminished conversion to 3H-dihydrotestosterone. Cyproterone acetate, on the other hand, did not affect 3H-testosterone metabolism. Estradiol-17β and cyproterone acetate inhibited in vitro binding of 3H-dihydrotestosterone to the intracellular cytoplasmic receptor, but not the intraluminal androgen binding protein (ABP). These data suggest that estradiol-17 β may have a more potent antiandrogenic effect on the epididymis than cyproterone acetate due to inhibition of 5 α reduction of testosterone as well as binding to the androgen receptor.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.