Expression of GnRH receptor gene in human ectopic endometrial cells and inhibition of their proliferation by leuprolide acetate

The present study was conducted to investigate whether GnRH-receptor (GnRH- R) gene is expressed in endometriosis ovarian implants and whether a GnRH-a nalogue (GnRH-a) may exert an effect on endometriosis cell proliferation in vitro. The presence of GnRH-R transcripts in ovarian endometriosis cells w as assessed by reverse transcription-polymerase chain reaction (RT-PCR) and further confirmed by Southern blot analysis. GnRH-R mRNA was detected in a ll the 13 samples examined. In contrast, GnRH-R transcripts were not detect able in endometriosis-free peritoneal tissue. In the second part of the stu dy, endometriosis cells were cultured for 9 days with different doses of le uprolide acetate (ranging from 0 to 10(-5) M). In 4 out of 13 cases, a sign ificant anti-proliferative effect was observed at doses of leuprolide aceta te ranging from 10(-9) to 10(-5) M. In one case, a significant inhibition o f cell proliferation was observed only at 10-5 M leuprolide acetate concent ration. In contrast, the GnRH-a did not affect cell growth, regardless of t he expression of GnRH-R transcripts and the given doses, in the remaining 8 experiments. To date, this is the first evidence indicating that GnRH-R mR NA is expressed in human ovarian endometriomas. Moreover, the inhibition of endometriosis cell proliferation induced by the GnRH-a in vitro suggests t hat, at least in some cases, this compound might exert a direct effect on e ndometriosis lesions. (C) 2000 Elsevier Science Ireland Ltd. All rights res erved.