Specifically, relaxin affects kidney arteries by revving up production of nitric oxide in a layer of cells lining the inside of blood vessels called the endothelium. Finding the key to this physiologic response could have significant implications for the treatment of hypertension and other cardiovascular diseases.
"This study, which mainly targeted small renal arteries isolated from rats, is consistent with our earlier work showing that relaxin increases renal blood flow and kidney filtration by as much as 40 percent in non-pregnant rats," said Kirk P. Conrad, M.D., senior study author and an investigator at the Magee-Womens Research Institute. The hormone causes similar increases in kidney function during pregnancy.
"Linking relaxin with nitric oxide is another peptide hormone called endothelin which has a receptor on endothelial cells that increases nitric oxide," he added. It is the action of endothelin and nitric oxide that increases dilation in the blood vessels, improving blood flow.
"What happens to the cardiovascular and renal systems during pregnancy is in many respects the antithesis of changes associated with aging," continued Dr. Conrad, who is also professor of obstetrics, gynecology and reproductive sciences and of cell biology and physiology at the University of Pittsburgh School of Medicine. "If we can discover the hormones responsible for these pregnancy changes and how they work, they might be useful for fighting high blood pressure and other cardiovascular diseases such as heart attack and stroke."
Cardiovascular disease remains the No. 1 killer of Americans.
Contact: Michele Baum
University of Pittsburgh Medical Center