Estradiol-17β- progesterone and 5α-dihydrotestosterone receptors of uterine myometrium and myoma in the human subject

Abstract

Steroid receptors in human uterine myomas and the corresponding myometria were characterized and investigated to clarify their relation to tumor growth. The 248,800 g supernatant of tissue homogenates was used, in which steroid receptors were characterized and determined by Scatchard plot analysis using dextran coated charcoal at 4°C. In cytosols of both myoma and moymetrium, the estrogen receptors (ER) were sedimented at approximately the 7S, 5S and 4S regions, and the estradiol-17β(E 2)-ER complex had a dissociation constant ( K D ) = 4.5 × 10 −10M. Progesterone receptors (PR) were sedimented at approximately the 7 S and 4–5 S regions. The K D of the progesterone-PR complex was 1.5 × 10 −9M and the K D of the R5020-PR complex was 5.0 × 10 −10M. Androgen receptors (AR) were sedimented at approximately the 6–7 S and 5 S regions and dihydrotestosterone (DHT)-AR complex had a K D = 4.0 × 10 −10M. All of steroid-7 S binding in the cytosol were easily degraded during 5–20% sucrose gradient centrifugation. Ligand specificity studies characterized the specificity of receptors. There was no significant difference in steroid receptor levels (expressed as fmol/mg protein) between myoma and the corresponding myometrium; however if the receptor level was expressed as fmol/μDNA, the estrogen receptor level in the myometrium was higher than that in the myoma ( P < 0.05). There was no significant difference in mitotic index between the two tissues.