Objective: To elucidate the mode of action of chlormadinone acetate (CMA) in reducing dysmenorrheic pain by studying the effects of CMA and dexamethasone (DEX) on messenger RNA (mRNA) abundance of cyclo-oxygenase-2 (COX-2), annexin-1 (ANXA1), glucocorticoid receptor (GR), progesterone receptor (PR), and concentrations of prostaglandin F(2α) (PGF(2α)) and leukotrienes B(4) (LTB(4)) and C(4) (LTC(4)) in human endometrial explants.
Design: Ex vivo study.
Setting: University hospital.
Patient(s): Fifteen premenopausal patients undergoing surgery for benign gynecologic disorders.
Intervention(s): Endometrial explants were obtained by aspiration curettage and stimulated ex vivo with interleukin-1β before exposure to CMA or DEX; mRNA levels were determined via reverse transcription-quantitative real-time polymerase chain reaction, and concentrations of arachidonic acid metabolites by enzyme immunoassays.
Main outcome measure(s): Messenger RNA levels of COX-2, ANXA1, PR, and GR; concentrations of PGF(2α), LTB(4), and LTC(4) in endometrial explants treated with CMA or DEX.
Result(s): In IL-1β-treated explants COX-2 mRNA and PGF(2α), concentrations were significantly down-regulated by CMA but not by DEX. Chlormadinone acetate did not affect mRNA abundance of ANXA1, PR, and GR.
Conclusion(s): Our data suggest that CMA is a suppressor of COX-2 expression. Comparison with DEX revealed that progestin-specific activity of CMA may mainly be responsible for suppression of prostaglandin biosynthesis in human endometrium.
Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.