Study suggests new therapy for impotence

October 27, 1999
Web posted at: 8:10 p.m. EDT (0010 GMT)

From Medical Correspondent Holly Firfer

DOCTOR Q&A: Read what doctors say about Viagra and impotence or ask your own questions.

IMPOTENCE: description risk symptoms treatment prevention Choose a link above to learn more about impotence. Source: WebMD

(CNN) -- Impotence used to be a taboo subject, a highly personal issue not to be openly discussed. But with the introduction of Viagra and public figures like Bob Dole announcing their personal battles with the problem, millions of people are talking about erectile dysfunction.

This public interest in impotence is one reason scientists are scrambling to find new treatments.

In a study reported in this week's editions of the medical journal Nature Structural Biology, researchers at the University of Pennsylvania say nitric oxide may hold the key to treating the problem. It's found naturally in the body and aids in smooth muscle relaxation, a requirement for erection.

"Nitric oxide is the messenger, if you will, the signaling molecule, and without that signal you can't get that signal from the brain to the penis for the erectile process," said Dr. David Christianson of the University of Pennsylvania.

An amino acid call L-argenine produces nitric oxide in the body. Researchers say they have found that a natural enzyme, argenase, that breaks down the L-argenine and renders it useless to make nitric oxide. This results in impotence.

What they have done is create an amino acid to stop this breakdown of L-argenine.

Erectile dysfunction affects half of the male population over 40 and according to Viagra makers Pfizer, their drug does not work in three out of 10 men.

"Their hopes have been so high, that when you get a patient and it (Viagra) doesn't work, they are depressed. They feel devastated by the problem," Urologist Steven Morganstern said.

According to the study's authors, Viagra works later in the erection process than this new therapy. They hope their findings may one day help Viagra work better as well as help those who are unable to take Viagra for medical reasons.

Continued testing is planned, but researchers warn it could be years before the therapy reaches the public.