Male contraception: a promising lead
Indeed, a team of scientists from Weill Cornell Medicine recently published results on mice in Nature Communications, regarding the use of a male contraceptive that could ultimately be on demand. Instead of acting on hormonal concentrations, this pill acts on sperm motility by inhibiting the activity of soluble adenylyl cyclase (sAC), an enzyme essential for spermatozoid activation.
The researchers showed that a single dose of this molecule immobilized mouse spermatozoids for 2.5 hours, after which their motility was gradually restored. Although the mating behavior of the mice remained unchanged after taking the inhibiting molecule, no pregnancy occurred in the group that was treated. In contrast, almost one third of the females were pregnant in the control group after being exposed to the male control mice.
Although this result is promising, other challenges must be met: in women, spermatozoids can survive for several days in the uterus following sexual intercourse. Therefore, the enzyme would need to be inhibited long enough to prevent passage through the cervix. In addition, although no side effects or toxicity have been noted after chronic exposure to this inhibitor, men and mice naturally deficient in sAC have a higher risk of kidney stones and high intraocular pressure than the general population.