Effect of exposure to ulipristal acetate on sperm function

ABSTRACT

Objective A pill containing ulipristal acetate (UPA) is used for emergency contraception (EC). Considering that, following its intake, spermatozoa may be exposed to UPA in the female genital tract we intended to evaluate sperm functions after incubation with this compound.

Methods Motile spermatozoa were selected by swim-up and were incubated under capacitating conditions with UPA (at concentrations of 1, 10, 100, 1,000, and 10,000 ng/ml) or control medium. The main outcome measures were sperm vitality, sperm protein tyrosine phosphorylation (TyrP), spontaneous acrosomal reaction (AR), and human follicular fluid (hFF)-induced AR.

Results Sperm vitality and TyrP pattern were similar between spermatozoa exposed to UPA or control. In addition, spontaneous AR ranged from 14.0 ±1.5% to 18.0 ±1.9% after exposure to UPA or control medium without significant differences, and UPA did not prevent hFF-induced AR.

Conclusions Incubation of sperm with UPA at concentrations around the expected plasma levels after ingestion of this EC pill (˜100–200 ng/ml) did not modify the signal transduction of TyrP involved in sperm capacitation. Moreover, UPA showed no agonist effect on progesterone receptors because it did not induce AR. Considering that progesterone in hFF is essential for AR induction, and UPA did not prevent the hFF-induced AR, an antagonist action of UPA on the AR is unlikely.

KEYWORDS:

• Spermatozoa
• Ulipristal acetate
• Acrosomal reaction
• Sperm function

ACKNOWLEDGEMENTS

The authors are indebted to Dr Régine Sitruk-Ware from the Population Council, New York, and to Dr Delphine Levy from HRA Pharma, Paris, France, for the kind donation of ulipristal acetate, and to Jenny Walldorf for the revision and suggestions of the early drafts of the manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and the writing of the text.

The study received partial funding (grant 573747/2008-3) from the Brazilian National Research Council (CNPq).