The finding, published in Nature Communications, could represent a breakthrough in efforts to develop a male contraceptive pill that men can take just before sexual activity and become fertile again the next day.
The study, coordinated by Jochen Buck of Weill Cornell Medicine (US), found that soluble inhibitors of an enzyme called adenylyl cyclase (sAC) can reduce sperm motility in mice and humans.
sAC is an essential enzyme that activates the sperm’s swimming and maturation abilities, allowing it to pass through the female reproductive system and fertilize an egg.
The team developed a substance called TDI-11816 that inactivates sAC. When injected into mice, it causes them to produce sperm that cannot grow and inhibits their maturation.
The compound did not affect the animals’ sexual behavior, but fertility disappeared within hours of administering the drug.
A single dose of this compound immobilizes mouse sperm for up to two and a half hours. After three hours, some of the sperm begin to regain their motility, and by 24 hours, almost all of them have regained their normal motility.
Read more: The first injectable contraceptive pill for men hits the market in 6 months
Contraceptive efficacy was 100% in the first two hours and 91% in the first three hours.
The study shows that no adverse health effects were observed with continuous administration of these drugs for six weeks.
While the drug was administered as an injection in most experiments, the authors also found that the mice’s sperm motility dropped to similar levels after oral administration.
A study by another team shows that men who lack the gene that codes for sAC are infertile but otherwise healthy, reassuring the team that inhibition of sAC may be a safe contraceptive option, the center told Weill Cornell Medicine.
“Our inhibitor works within 30 minutes or an hour,” said Melaine Balbach, another signatory. “All other experimental hormonal or non-hormonal male birth control pills take weeks to lower sperm counts or prevent eggs from fertilizing.”
The scientist believed that since the effect of sAC inhibitors wears off within a few hours and men will take them only when and as often as needed, they could empower them to make day-to-day decisions about their fertility.
The researchers say their study provides proof-of-concept that soluble adenylyl cyclase inhibitors have the potential to provide a safe, on-demand, nonhormonal, reversible oral contraceptive for men.
The team needs more research to determine whether these drugs work effectively in humans and to identify possible side effects, and is currently working to make sAC inhibitors more suitable for human use.
In addition, Buck said he will repeat the experiments in another animal model, which will lay the groundwork for human clinical trials that will confirm the effect of sAC inhibition on sperm motility in healthy men.
Researcher Lonny Levin said research on oral contraceptives for men has stalled in part because potential male contraceptives must meet a much higher bar for safety and side effects.
In this sense, he pointed out that since men do not take the risks of pregnancy, they are believed to be poorly tolerated by the potential side effects of contraceptives.
Source: Ultimahora
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Karen Clayton is a seasoned journalist and author at The Nation Update, with a focus on world news and current events. She has a background in international relations, which gives her a deep understanding of the political, economic and social factors that shape the global landscape. She writes about a wide range of topics, including conflicts, political upheavals, and economic trends, as well as humanitarian crisis and human rights issues.
