April 21, 2004 -- An experimental drug may be able to prevent some of the weight gain many women experience after menopause.
According to researchers, menopause can be a time where many women gain, on average, 10-15 pounds. While the exact cause of the weight gain is unknown, hormones may play a part.
An experimental drug that has estrogen-like effects was shown to reduce by almost half the normal weight gain associated with menopause. But researchers warn that the experimental drug, known as PPT, also causes abnormal uterine growth that could lead to cancer.
The findings were presented at the Experimental Biology 2004 research meeting in Washington, D.C.
In the study, researchers gave either PPT or a placebo to rats in daily injections for 21 days. The rats' ovaries were removed to mimic the loss of hormones that occurs during menopause.
Rats who received placebo injections gained an average of 30% of their body weight after 21 days. Meanwhile, those treated with PPT gained an average of 17%.
PPT works in a similar way to the widely used drugs tamoxifen -- which prevents breast cancer recurrence -- and Evista -- which prevents and treat osteoporosis. But the popularity of these drugs has been dampened by concerns about tamoxifen's higher uterine cancer risk and risk of blood clots associated with both drugs.
Those shortcomings are leading many researchers to search for newer ways to slow the weight gain associated with menopause without promoting dangerous side effects.
That did not happen with PPT because the rats still developed dangerous uterine growth.
"It's not a perfect drug. We're still trying to make that perfect drug," says lead researcher Darren M. Roesch, PhD, assistant professor of physiology at Georgetown University.
'Puzzling It Out'
Researchers already know that drugs like PPT can have different effects in different parts of the body. So it is theoretically possible to design a drug that stops weight gain while not promoting cancer, says John Katzenellenbogen, a University of Illinois chemist who designed PPT along with his wife, Benita, a physiologist.
But can researchers design a drug with the right combination of effects?
"It's possible. It's not clear how one would do this. People have to puzzle it out now," he tells WebMD.
The researchers say that the study represents a good "proof of concept" to show that PPT and half a dozen related compounds could work. They conclude that drugs that work on this estrogen receptor may prove to be useful therapeutically to reduce postmenopausal weight gain in women.
Researchers are hard at work trying to create these drugs. Still, it is likely to be three to five years before any of the experimental drugs is ready for human testing, Katzenellenbogen says.