Dr. Eaton and his colleagues examined genetic, hormonal and pharmacologic changes that affect the sodium channels, which are special protein molecules found in a type of kidney cell. Sodium channels act as a gatekeeper by retaining salt in the kidney or by allowing it to enter the bloodstream in response to changes in blood pressure. Small alterations in these molecules cause them to retain too much salt, which can lead to high blood pressure. About 30 percent of people who have hypertension, or high blood pressure, are reacting to the buildup of too much sodium.
"If the sodium channels are too active," says Dr. Eaton, "then people retain sodium, causing water buildup and an abnormal rise in blood pressure."
Hypertension affects an estimated 62 million Americans and is an underlying cause of heart attacks, heart failure and strokes, as well as kidney failure. Some people have a specific, genetic abnormality that affects the sodium channels, but in other people there is nothing obviously wrong.
"In this other group of people, the sodium channels are switched on or off incorrectly by another molecule," says Dr. Eaton.
The steroid hormone aldosterone regulates how much sodium is released or
retained by the sodium channels. In turn, steroid hormones like aldosterone
work by switching on and off
Contact: Sarah Goodwin
Emory University Health Sciences Center