Researchers working on a project funded by the National Institutes of Health (NIH) have discovered a molecule that increases the activity of sperm cells so they can travel to egg cells. The identification of this molecule can potentially be used in male contraceptives and treatments for infertility based on problems with sperm mobility.
While sperm cells in the male reproductive tract are capable of movement, this range of motion is not nearly enough to allow them to reach the egg in the female reproductive tract. In order for them to complete this trip, they are activated by progesterone, a hormone released by the egg.
According to a recent study published online in Science, the molecule to which progesterone binds is the enzyme alpha/beta hydrolase domain containing protein 2 (ABHD2).
Before sperm becomes hyperactive, calcium enters its flagella. The sperm protein CatSper joins with similar proteins in the flagella to propel the sperm to the egg. Upon conducting their investigation, the researchers found that CatSper is not involved in triggering the calcium. The researchers then moved on to isolate ABHD2 from the flagella. When ABHD2 was inactive, the sperm cells could not be activated by progesterone, confirming the researchers’ beliefs that ABHD2 is the molecular target of progesterone.
“This is an important advance in explaining how sperm become hypermotile in the female reproductive tract,” Stuart Moss, director of the male reproductive health program at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a press release. “Developing new compounds that block ABHD2 ultimately may yield new contraceptive methods to prevent sperm from reaching the egg.”