Relationship between gonadotropin-releasing hormone/gonadotropin-releasing hormone receptor signaling and progesterone receptors in human trophoblasts

OBJECTIVE: To investigate the relationship between gonadotropin-releasing hormone (GnRH)/gonadotropinreleasing hormone receptor (GnRHR) signaling and progesterone receptors (PGRs). STUDY DESIGN: HTR-8/SV neo cells and JEG-3 cells were incubated for 24 hours with GnRH-I or -II. The expression of PGRs was measured by quantitative realtime reverse transcriptase-polymerase chain reaction and Western blotting. RESULTS: In both cells lines after incubation with 1-1,000 nM/L GnRH-I or -II the ratio of PGR-B to PGR-AB mRNA level did not differ in any of the groups as compared to the control. Relatively higher expression of PGR-B than PGR-A mRNA and expression of only PGR-B protein without PGR-A protein were observed in all specimens. There were no significant differences in the expression of PGR-B protein in each group when compared to the control group after incubation with GnRH-I or -II at 0.001-1,000 mM/L in both cell lines. CONCLUSION: PGRs are expressed regardless of GnRH/GnRHR signaling in human trophoblasts, in which PGR-B expression is more dominant than PGR-A expression.