INCREASED PROGESTERONE RECEPTOR CONCENTRATIONS IN BLADDER LESIONS OF ESTROGEN-TREATED SYRIAN-HAMSTERS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 39  (7) , 2614-2617
Abstract
During studies of renal tumorigenesis induced by estrogen in Syrian hamsters, .apprx. 15-20% of animals develop bladder lesions with an increased wet wt of tissue from 0.2 g-0.4-1.7 g. Histological examination of the lesions showed a spectrum of changes from inflammatory reactions to squamous metaplasia and intense hyperplasia of the transitional epithelium. The concentration of progesterone-binding sites was increased in the bladders with lesions. No specific progesterone-binding sites could be detected in the cytosol of bladders from hamsters not treated with estrogen. The affinity constant for the progesterone-binding sites in cytosol from bladders with lesions was 109 M-1, the same as that reported for progesterone receptors in other target tissues for estrogen. The binding sites are specific for progesterone and are not competed for by 17.beta.-estradiol, 5.alpha.-dihydrotestosterone, or aldosterone.