Steroid receptors of the uterine myometrium, myoma, adenomyosis and ovarian endometriosis in the human subject

Abstract

Steroid receptors in benign human uterine tumors and disorders were characterized and investigated to clarify their clinical significance. A 248,800 x g supernatant of tissue homogenates was used for the cytosol, where the steroid receptor was characterized and determined by a Scatchard plot. In the myometrial cytosol, the estrogen receptor (ER) was sedimented to the 7S, 5S and 4S regions, and the estradiol-17β (E2)-ER complex demonstrated the dissociation constant (Kd) = 4.5x1010 M at (4° C, by dextran coated charcoal DCC). The progesterone receptor (PR) was sedimented to the 7S and 4S regions, and the Kd of the progesterone-PR complex was 1.5 x 10-9M (at 4°C by DCC). The androgen receptor (AR) was sedimented to the 7~6S and 5S regions, and the dihydrotestosterone (DHT)-AR complex demonstrated Kd = 4.0 x 10-10 (at 4°C by DCC). All of these steroid-7S bindings were easily degraded during sucrose gradient centrifugation. A ligand specificity study characterized the specificity of the receptors. There was no relation between the steroid receptor level in the myometrium and the corresponding myoma. The steroid receptor level was determined during the menstrual cycle and did not show a constant tendency. In adenomyosis, the histological dating showed a delay in the aberrant endometrium of adenomyosis when compared with the dating of a normal endometrium. This indicates that the steroid is less responsive to the aberrant endometrium in adenomyosis than to the corresponding normal endometrium. ER and AR were detected in all cases, but PR was not detected in some of them. Thus it would seem that the lower responsiveness of adenomyosis tissue to progestogen is derived from the lower content of PR. In most cases of endometriosis the steroid receptor was detected; however, the level of PR in endometriosis was much lower than that of a corresponding normal endometrium. This indicates that most cases of endometriosis respond to steroids, but to a lesser extent than to progestogen.