Male Birth Control Pill Stops Sperm in Brain
Posted by Nick Timiraos
It's been almost ten years since Pfizer brought Viagra to the market. Now, researchers are working to crack the code on what could be another sexual health miracle: a male birth control pill.
This morning at a meeting of the American Association of Pharmaceutical Scientists, researchers described early work in rats on a pill that one day could render men temporarily infertile. The key is something called a selective androgen receptor modulator, or SARM. "These compounds suppress a brain hormone, and shut down sperm production in a reversible way," Jim Dalton, vice president of research and development at GTx, tells the Health Blog. GTx, based in Memphis, Tenn., specializes in hormone treatments for cancer and men's health.
To achieve birth control, men would have to take such a pill for two to three months to deplete their sperm. It would take about the same amount of time for them to return to full reproductive capacity after stopping the medicine. Even if all goes well, any pill is still five to 10 years away.
But in rats, the experimental drug, referred to as "C-31," achieved 100% infertility at a dose of just a tenth of a milligram a day. Some 83% of rats treated with the drug regained fertility 70 days after treatment, according to an summary of the presentation. At 100 days, the fertility rate was 100%. The work was supported by a grant from the National Institutes of Health.
Many pharmaceutical companies are doing research in SARMs, which may help combat muscle and bone loss. Last week GTx inked a research pact with Merck on development of drugs for those uses.
A male contraceptive using SARMs could have the positive side effect of boosting muscle mass for users. "They're not going to be disappointed with that," says Dalton, also a professor at Ohio State University.
But the rats in the study didn't gain or lose muscle mass. And their prostates shrank, an undesirable side effect. So there's still plenty of work to be done before any drug from the work is ready for men.
Louis J Sheehan
Recent discussions in the birth control forum (2 discussions)
|i think all girls should be on birth control til' they're 24 years old!||148||Feb 10, 2008|
|C-31 Louis J Sheehan||0||Nov 17, 2007|