David Christianson and his research team have new hope for anyone suffering from sexual dysfunction. The Penn team, in collaboration with researchers at Temple University, Boston University, the University of Pittsburgh, the Wistar Institute and Universite Paris V, have discovered the role of the enzyme arginase in the chemical system that allows physical arousal to take place. "This is the first publication... that demonstrates that arginase is present in human tissue and the inhibition of that arginase can cause a smooth muscle relaxation, which is a requirement for erection," Christianson said. The researchers have also discovered a molecule that can bind to arginase, rendering it inert. This offers hope for individuals -- both men and women -- who are suffering from levels of arginase that are too high to allow the necessary smooth muscle relaxation to take place. However, any drug based on the research is many years away. "The process of drug discovery is a 10-year process, so what we've done now is we've identified a bona fide drug target," Christianson said. "That's just the first step. The next step is to study the action of an arginase inhibitor in a living system." Arginase acts in the body to regulate the production of nitric oxide, a crucial signalling molecule in the system that regulates smooth muscle relaxation. When it is present in excessive quantities, it prevents the chain reaction from going forward. Therefore, an inhibitor like BEC can return arginase levels that let arousal take place. "Both Viagra and BEC function by blocking enzymes that can degrade key chemical players in this pathway," Christianson said in a statement. "The difference is that Viagra works several steps later than arginase-inhibiting compounds." Viagra is ineffective in 30 percent of the men who try it and much less effective in women. David Ash, a biochemistry professor at Temple University who collaborated with Christianson's team, said that working at different sites did not present the researchers with major problems. "There are just a few logistical things we have to deal with once in a while," Ash said. "This is the way science is done these days." Christianson's peers at Penn had only praise for his work. "It's an excellent example of how basic structural and mechanistic studies in biological chemistry can lead to the development of compounds of therapeutic value," said Barry Cooperman, a fellow biochemistry professor. "I think it's tremendous," said Jeffery Saven, another biochemistry professor. "[Christianson is] just a great scientist." Saven noted that Christianson and his team are experts in both synthesizing new chemicals and determining their structure and function. The research is scheduled to be published in two papers in the March 13 issue of Biochemistry.
The Daily Pennsylvanian is an independent, student-run newspaper. Please consider making a donation to support the coverage that shapes the University. Your generosity ensures a future of strong journalism at Penn.
DonatePlease note All comments are eligible for publication in The Daily Pennsylvanian.
