A study of the body system that deals with Americans' love affair with salt may yield more insight into why so many end up hypertensive and how to better treat them.
A team of scientists from the Medical College of Georgia, the University of Utah and the University of Texas at San Antonio is looking at how the kidneys know you've eaten too much salt and what they do to eliminate it. The work is funded by a $11.2 million National Institutes of Health Program Project grant.
Their focus, endothelin, ironically has a bad rep as a "death peptide" because of its shared ancestry with the Israeli burrowing asp that can shut down coronary arteries with one bite.
But the powerful protein produced by the kidney takes direction good or bad from its receptors, according to Dr. David Pollock, renal physiologist at MCG's Vascular Biology Center and director of the program project
"It's like politics: all things are local," said Pollock. In this case the upright guy tends to be the B receptor, which aids sodium excretion while its roguish sibling A receptor the same one that shuts down the coronary arteries of asp victims blocks it. When all goes well, the balancing act regulates the sodium level with the kidneys producing more endothelin and B receptors to eliminate the excess.
However in hypertension models, the B receptor doesn't work so well, although exactly why is still unclear. "It's this balance between A's and B's that is critical," Pollock said. "If your balance becomes unbalanced you will have salt-sensitive hypertension." That's why he is looking at the pathways that become activated on a high-salt diet and just what the A receptor is up to.
He and his colleagues are studying rats deficient in B receptors; they are a slightly hypertensive on a regular diet and very hypertensive on a high-salt diet. More circuitously, the researchers also infused angiotensin, a powerful blood vessel constrictor, into ra
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Medical College of Georgia