Gonadotropin‐releasing hormone (GnRH)‐I regulation of interleukin (IL)‐1b and IL‐1 receptor antagonist expression in cultured human endometrial stromal cells

Abstract

Human endometrium is an active site of cytokine production and action. Among these cytokines, the interleukin-1 (IL-1) system seems to be relevant to the embryonic implantation process. We have previously reported the production of GnRH-I by human blastocyst, as well as the presence of GnRH-I receptor in human endometrium. This suggests a close interaction between the immune and endocrine systems through these cytokine mediators in embryonic implantation. To test the relevance of this interaction during embryonic implantation, we investigated GnRH-I regulation of IL-1b and IL-1ra mRNA and protein expression in human endometrial stromal cells using quantitative competitive polymerase chain reaction and ELISA. IL-1b mRNA and protein expression in cultured human endometrial stromal cells was significantly enhanced by GnRH-agonist in comparison to control groups. IL-1ra mRNA and protein was significantly decreased by GnRH-agonist in comparison to control groups. In contrast, the GnRH-antagonist ablated the regulatory effects of GnRH agonist in 1b and IL-1ra mRNA and protein levels in a dose-dependent manner. In conclusion, these results suggest a possible close interaction between the immune and endocrine systems in human embryonic implantation through the classical neuropeptide hormone GnRH and its receptor.