GONADOTROPIN-RELEASING-HORMONE (GNRH) RECEPTOR AND STEROID-RECEPTORS IN HUMAN UTERINE LEIOMYOMA, MYOMETRIUM AND ENDOMETRIUM

The present study evaluated the presence of GnRH-R in leiomyomas, in a ssociated, non-involved uterine tissues (myometrium and endometrium) a nd the possible relationships between GnRH-R and the receptors for est rogen and progesterone in the same tissues. GnRH-R was found in all ut erine tissues and both GnRH and the GnRH analog, goserelin, displaced its binding consistent with a single type of high affinity receptor (K d approximate to 10(-8) M). GnRH-R were found more frequently in myome trium (81% of samples) than in endometrium (58%) or leiomyoma (42%). H owever, the mean receptor content was lowest in myometrium (139+/-19 f mol/mg protein) with both leiomyomas (288+/-77 fmol/mg protein) and en dometrium (372+/-96 fmol/mg protein) having significantly higher value s. Endometrial GnRH binding varied from 596+/-42 in uteri that were Gn RH-R positive in the endothelium alone to 231+/-49 when GnRH-R was pre sent also in the other tissues. Endometrium negative for the GnRH-R ha d significantly higher levels of estrogen receptor than all the other uterine samples (266+/-25 vs 61+/-7.5 fmol/mg protein, respectively). Endometrial GnRH-R seem to be dependent on its presence and/or level i n other uterine tissues. Further, when GnRH-R is absent in the endomet rium this tissue expresses greatly increased levels of steroid recepto rs.