U.S. researchers have stumbled on a compound that may finally lead to a birth control pill for men.
In lab experiments, male mice given the pill were rendered completely infertile during treatment as they produced fewer and less mobile sperm. The drug, originally tested as part of a broader cancer research project, does not affect the hormone system or sex drive, the team said on Thursday.
"There is no effect on the mouse's mojo. The animals exhibit the normal sexual behaviors and frequency of copulation," said Dr. James Bradner of the Dana-Farber Cancer Institute in Boston, whose study appears in the journal Cell.
The effect is completely reversible. Once doctors stopped giving the drug to mice, they were able to sire healthy litters, with no apparent side effects, Bradner said.
Scientists say the research is exciting because it applies a unique approach to the problem of male contraception, which is now largely composed of less-reliable methods like condom use, or more permanent procedures like vasectomies.
Bradner's lab focuses on developing new drugs to undermine the molecular memory of cancer cells that tell them to divide.
Those memory markers are distributed throughout the genome, the DNA that makes up a person's genetic code, and Bradner likens them to post-it notes that give cells instructions.
The team was experimenting with a compound developed in Bradner's lab called JQ1, which was originally synthesized at Dana-Farber to block BRD4, a cancer-causing gene.
They discovered that it appears to target a protein specific to the testes called BRDT that instructs sperm to mature. Bradner said the compound does not seem to damage sperm-making cells, but they forget how to create mature sperm while under its influence.
