New York - Robert F. Furchgott, a scientist who won a share of a Nobel Prize and whose work helped lead to the development of Viagra, has died. He was 92.

His daughter Susan Furchgott confirmed to The New York Times that the pharmacologist died Tuesday in Seattle.

Furchgott worked with the gas nitric oxide, which led to new research in cardiovascular functions. Nitric oxide had been known as a pollutant that contributed to smog and acid rain, but research by Furchgott and others found it was an important signal in the cardiovascular system, mediating blood pressure and blood flow.

The scientists were praised when they were awarded the Nobel Prize for physiology or medicine in 1998 for providing the first proof that a gas can perform important biochemical functions in the body.

Furchgott was born in Charleston, S.C., and developed an early interest in birds and shells. He enjoyed reading books about scientists.

He earned a chemistry degree from the University of North Carolina and a doctorate in biochemistry from Northwestern University. Before coming to SUNY Downstate in 1956, he taught and researched at Cornell and Washington Universities. He was chairman of Downstate's pharmacology department from 1956 until 1982.