Effects of androgen on embryo implantation in the mouse delayed-implantation model

<bold>Objective: </bold>To examine the effects of androgen on implantation and decidualization in the mouse delayed-implantation model. <bold>Design: </bold>Experimental animal study. <bold>Setting: </bold>University research laboratory. <bold>Animal(s): </bold>Sexually mature female mice (Kunming White strain). <bold>Intervention(s): </bold>Delayed and activated implantation; pseudopregnancy; embryo transfer (ET); E(2) assay; inhibitor. <bold>Main Outcome Measure(s): </bold>Effects of androgen on embryo implantation were determined by treating the mice under delayed implantation with different doses of testosterone propionate (TP); the effects of androgen on the expression of implantation-related genes were examined by in situ hybridization. <bold>Result(s): </bold>Delayed implantation could be initiated by TP. Dihydrotestosterone was also able to initiate implantation in the delayed-implantation model. The implantation window could be maintained for at least 48 hours by 5 mg TP per mouse. Prostaglandin endoperoxide synthase 2 (Ptgs2) and microsomal prostaglandin E synthase (mPtges) were aberrantly expressed in mouse uterus at implantation sites after delayed implantation was activated by high doses of TP. <bold>Conclusion(s): </bold>A low dose of TP led to a delay in embryo implantation, but a high dose caused aberrant expression of both Ptgs2 and mPtges at the implantation site. It is possible that high doses of TP may disturb peri-implantation development or may be involved in early pregnancy loss by disturbing the uterine prostaglandin system. [ABSTRACT FROM AUTHOR]