Objective: To study the mechanism of action of prostaglandin E2 (PGE2) and its analogue sulprostone leading to production of glycosaminoglycans (GAGs) in the human uterine cervix.
Study design: We analysed the effects of PGE2 and its analogue sulprostone upon production of adenosine 3',5'-monophosphate (cAMP), in human cultured fibroblasts. We also studied the effects of PGE2, sulprostone and a cAMP analogue (8-Bromo-cAMP), on the incorporation of [3H]glucosamine into GAGs in human cervical fibroblasts in culture.
Results: Following treatment with PGE2 (10(-4)-10(-6) M), we observed a significant increase in the production of cAMP from 96.3 +/- 8.4 pmol/10(6) cells without phosphodiesterase inhibitor 3-isobutyl-methylxanthine (IBMX) to 325 +/- 63 pmol/10(6) cells with 10(-4) M IBMX (Spearman correlation test; P < 0.05). Under the same conditions, the effects of sulprostone (10(-6) M) were limited (from 8.1 +/- 1.5 to 51.3 +/- 14.1 pmol/10(6) cells without and with IBMX, respectively; not significant). Both PGE2 and 8-bromo-cAMP (from 10(-12) to 10(-4) M) increased [3H]glucosamine uptake into GAGs (Spearman correlation test; P < 0.05). Sulprostone (10(-12)-10(-4) M) was unable to reproduce such an effect even after a 24 or 48 h treatment.
Conclusion: Since firstly, PGE2 acts through EP1, EP2 and EP3 specific receptors, whereas the action of sulprostone is only mediated by EP1 and EP3, and secondly EP2 receptor is coupled with cAMP production, we conclude that cAMP is involved in mediating the action of PGE2 upon GAG synthesis by human cultured cervical fibroblasts.