Androgen, estrogen and progesterone receptors of the R3327H Copenhagen rat prostatic tumor.

Sucrose density gradient analysis of the R3327H tumor cytosol demonstrated the presence of both androgen and estrogen binding proteins. Competitive binding analysis with 17 beta-estradiol, 5 alpha-dihydrotestosterone, R1881, cyproterone acetate, and cortisol was consistent with the presence of 2 different binding sites for androgens and estrogens. Scatchard binding analysis was performed in the dorsal-lateral prostate as well as the R3327H tumor from normal Copenhagen rats. High affinity receptors for androgen and estrogen but not progesterone were found. However, in R3327H tumors relapsing following castration, the presence of high affinity receptors for progesterone were readily detectable.