Test Drug Increases Sex Drive in Rats

Wednesday, June 30th 2004, 9:25 am
By: News On 6

WASHINGTON (AP) _ Could a Viagra for women be in the offing? Well, female rats given a drug that mimics a pituitary hormone began giving ``come hither'' signals to nearby males.

The drug, called PT-141, is also being tested as a treatment for erectile disfunction in men and seems to operate through a central mechanism in the brain, said lead researcher James G. Pfaus of Concordia University in Montreal.

How it works isn't yet clear, he said, but female rats given the drug darted around to attract the attention of males, and assumed postures that invited sexual activity, the researchers reported.

Pfaus said the research was paid for by Palatin Technologies of Cranbury, N.J., the maker of PT-141, which requested him to run the tests. He said the source of the funding had no influence the outcome of the experiments. The report is published in Monday's issue of Proceedings of the National Academy of Sciences.

``This is the first step in really trying to understand sexual desire in the brain,'' Pfaus said. ``We hope it will lead to better treatments that women can use themselves for themselves.''

This is not something all women need, Pfaus added. It could be useful for women who are sexually functional, lose that desire but don't want to accept the loss, he said.

Palatin is conducting phase one tests of PT-141 in women, he said. Such tests are mainly intended to evaluate the safety of a product, and only after that is established can researchers move on to test for effectiveness.

PT-141 is also being tested in males and improved their erectile response, according to a report in the International Journal of Impotence Research. At higher doses, however, some men experienced nausea.

Federal regulators may be reluctant to approve a sexual dysfunction product that has such a side-effect, commented Dr. Allen D. Seftel of Case Western Reserve University in Cleveland.

Seftel, who was not part of the research team, said the researchers' animal model appears to be sound.

If approved, PT-141 would be the first drug to treat female sexual dysfunction.

While there are several products on the market to help treat sexual disfunction in males, little is available to women and this has been an area of increasing study in recent years.

Procter & Gamble is conducting tests of a testosterone patch for women. A mechanical product called Eros, designed to increase blood flow to the clitoris, was approved by the Food and Drug Administration in 2000.

In the PT-141 study the female rats did not increase their overall amount of activity, Pfaus said, but did more movements that are typical of sexual overtures to attract males.

Women don't posture the way rats seeking sex do, he noted.

But, Pfaus said, ``Women let us know they're there and do social behaviors that let us know that they're interested.''

He said that the researchers are working with female rats to see where in the brain cells are activated for increased sexual desire.

The biggest payoff, Pfaus said, may be that by studying how PT-141 works researchers may be able to determine from where sexual desire emanates.