Researchers at the University of Virginia School of Medicine found that targeting an enzyme in the testes decreases sperm motility or prevents the sperm from swimming to the egg. Their study journal Protein Expression and Purification states that this may pave the way for male contraception without the side effects that other hormonal contraception cause.

“The milestone reached is the production and isolation of a full-length, active kinase enzyme in sufficient quantities to conduct drug screens,” explains John Herr, a researcher from the University of Virginia School of Medicine as well as the director of UVA’s Centre for Research in Contraceptive and Reproductive Health. “Isolation of an active, full-length form of this enzyme allows us to test drugs that bind to the entire surface of the enzyme so that we can identify inhibitors that may exert a selective action on sperm.”

The enzyme can only be found in the cells known as spermatids located in the testes. These cells produce sperm so specifically targeting this function will inhibit the sperm to fertilise the egg.

male contraception

The new form of male contraception being developed at the University of Virginia School of Medicine aims to stop sperm (pictured) from swimming to the egg. Photo from UVA Health System

Since the enzyme cannot be found in other body parts, the drugs that would be programmed to target this would only focus on this enzyme, preventing any side effects to other body parts. This solves the problem of current contraception that can cause side effects in healthy individuals.

“Because a male contraceptive treats an otherwise healthy person, it’s going to have to be very safe and efficacious, without side effects. Thus contraceptive research has a much higher bar [than in other forms of drug development], and it’s going to take a determined march to reach the goal of a new, reversible contraceptive option for men,” Herr said. “We’re on the path toward the male contraceptive drug, and this is a noteworthy benchmark along that path,” he added.

“We believe this in an important contribution to our male contraceptive research, allowing us to identify male contraceptive drug candidates targeting the testes-specific kinases,” says research scientist Jagathpala Shetty. “So far there are no kinase drugs in use in contraceptive research, so this will be one of the first efforts to identify a drug inhibiting testes-specific kinase function.”

Nevertheless, Herr admits that more studies are still needed. Still, the researcher hopes that the study will open the way for a new contraceptive that can be taken by healthy men without affecting other body parts.