Raising Hope For Male Contraception

The search for a male contraceptive pill has been stymied by two major problems: To date, most therapeutic strategies lead to either irreversible infertility or unwanted changes to male sexuality. Now, a research report suggests a new approach that could sidestep these problems. Sabatino Ventura of Australia’s Monash University and colleagues propose that scientists working on male contraceptives should focus on blocking the action of two proteins required for sperm to be transported from the vas deferens into semen during ejaculation (Proc. Natl. Acad. Sci. USA 2013, DOI: 10.1073/pnas.1318624110). The team, working with mice, first knocked out the genes for these proteins, called α_1A-adrenergic G protein-coupled receptor and P2X1-purinoceptor ligand-gated ion channel. “This modification produced 100% infertility without effects on sexual behavior or function,” the researchers note. To determine the effect on male mice’s fertility, the team used sperm extracted from the knockout mice to successfully fertilize an egg. The loss of the two genes didn’t affect sperm production, only its transport. If the work is translatable from mice to men, molecules that block the action of the proteins could form the basis of a male pill.