Abstract
Clinically, Dehydroepiandrosterone-sulfate (DHAS) has been used to ripen uterine cervix. In order to clarify the mechanism of direct effect of DHAS on human uterus, an attempt was made to find DHAS specific binding protein in human uterine cytosol. Myomerium were obtained from the patient with uterine myoma at hysterectomy, pulverized and homogenized. Cytosol fraction was obtained by centrifugation at 105, 000xg for 60min. After removal of intrinsic steroids with 0.5% DCC, cytosol was added with 100M3H-DHAS and incubated for 12hours. Perotein bound 3H-DHAS was separated from free3H-DHAS by Sephadex G-25M gelfiltration. All procedure were performed at 4°C. Two radioactive peaks were found ; one at Fr. No. 17. and the other at Fr. No. 50. The first peak was considered to be protein bound since the fraction was studied by addition of excess amount of steroids in incubation system. An addition of DHAS binding, percent binding of DHAS was not altered by the addition of estradiol, progesterone (P4), 20-α-OH-P4, DHA and dihydrotestosterone. Inhibitory effect of DHAS was dose dependent.14C-DHAS incubated with myometrial cytosol for 2 hours at 37C°was recovered as unchanged form, indicating that the radioactive peak found in protein fraction was DHAS. From the results obtain above, it is suggested that cytosol of human myometrium possess the capacity to bind DHAS specifically.
