Peter Agre and Roderick MacKinnon of the United States have won the 2003 Nobel Prize for Chemistry. The Royal Swedish Academy of Sciences says the two biochemists will share the $1.3 million award for their research into how salts and water are transported into and out of the cells of the human body.

The academy says the work of the two scientists on cell membranes has provided crucial insights into many diseases affecting humanity.

It specifically mentions that their discoveries have provided an understanding of how the kidneys recover water from primary urine and how the electrical signals in nerve cells are generated and propagated.

Peter Agre works at the Johns Hopkins University School of Medicine in Baltimore. Roderick MacKinnon is attached to Rockefeller University in New York.

The Swedish Academy, which gave out the award, says their research into so-called channels in cell membranes is considered particularly valuable in treating illnesses affecting the kidneys, heart, muscles and nervous system.

This year's Nobel awards season began last week, when South African writer J.M. Coetzee was given the prize for literature.

On Monday, Paul Lauterbur, of the United States, and Peter Mansfield, of Britain, were awarded the medicine prize for their discoveries related to magnetic resonance imaging. And on Tuesday, three quantum physicists - Russo-American Alexei Abrikosov, Russian Vitaly Ginzburg, and British-American Anthony Leggett, were given the physics prize for their work on the theory of superconductors and superfluids.

The winner of the economics prize will be announced later Wednesday.

The most prestigious of the Nobel awards, the peace prize, will be announced in Norway on Friday.