Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Enzyme affects hypertension by controlling salt levels in body

07.07.2005


An enzyme known to cause hypertension increases blood pressure by activating tiny pores, or channels, in kidney cells that allow increased levels of sodium to be reabsorbed into the blood, researchers at UT Southwestern Medical Center have found. The findings shed light on the underlying mechanisms that cause hypertension, and may also help explain why patients with hypertension linked to salt intake often need to take potassium supplements in order to keep their high blood pressure in check.



The study will appear in an upcoming issue of the Proceedings of the National Academy of Sciences. "This is a classic example of how basic research could lead to better understanding of human diseases and potentially to new therapeutic methods," said Dr. Bing-E Xu, assistant professor of pharmacology at UT Southwestern and lead author of the study.

The enzyme WNK1 is known to cause a form of hypertension, abbreviated PHA II, but until now the method by which it affected blood pressure was unclear. By studying animal and human cells in culture, UT Southwestern researchers determined that WNK1 interacts with and activates another enzyme, SGK1, which is well known to lead to the activation of sodium ion channels in kidney cells.


"The kidney plays a very important role in controlling blood pressure by controlling how much sodium gets reabsorbed back into the kidney and the blood," said Dr. Chou-Long Huang, associate professor of internal medicine at UT Southwestern and co-senior author of the study. "Sodium comes into the kidney cell through these channels and is then returned to blood circulation through another sodium transporter," he said. "The sodium channel critically governs how much sodium gets reabsorbed."

Normally, the kidney filters and reabsorbs about 99 percent of sodium from the blood and returns it to the body, excreting 1 percent through urine, said Dr. Huang, a nephrologist.

However, if salt ingestion remains the same and the kidneys reabsorb 99.9 percent of salt, too much salt returns to the blood, increasing blood volume and leading to hypertension. If less than 99 percent is absorbed, low blood pressure develops.

Dr. Huang said that not everyone who eats too much salt ends up with hypertension, but some population groups, such as African-Americans, are more prone to develop salt-sensitive high blood pressure, suggesting that genetic factors may play a role in the disease.

One extension of the current work may lead to a better understanding of hypertension that is induced by low potassium intake. Previous studies have shown that diuretics, a class of drugs commonly used to control hypertension, also cause potassium wasting, or low potassium levels, in patients.

"Studies have shown that if you are taking diuretics and let your potassium level fall, the diuretics are not as effective," Dr. Huang said. "But if you take diuretics and you supplement with potassium, you can lower blood pressure more effectively." Dr. Huang and his research group currently are conducting studies to determine whether low potassium intake increases WNK1 activity, leading to hypertension.

The WNK1 enzyme was first identified and cloned in 2000 by UT Southwestern researchers led by Dr. Melanie Cobb, co-senior author on the PNAS paper and dean of UT Southwestern Graduate School of Biomedical Sciences. After cloning the enzyme, Dr. Cobb’s research group examined what proteins might be regulated by WNK1, and found that SGK1 was one of those proteins. Because he works on ion channels, including sodium channels, Dr. Huang joined efforts with Dr. Cobb to study how WNK1 regulates sodium channels.

"We have been working on WNK1 for several years now and these findings are unexpected from initial studies," said Dr. Cobb. "What is particularly satisfying and exciting is the ease with which we could establish such a collaboration at UT Southwestern to study the physiological and medical implications of our findings."

Other UT Southwestern researchers involved in the study were Steve Stippec, pharmacology research associate; Dr. Ahmed Lazrak, instructor of internal medicine; Dr. Xin-Ji Li, research associate in internal medicine; Dr. Byung-Hoon Lee, postdoctoral researcher in pharmacology; and Dr. Bernardo Ortega, postdoctoral researcher in internal medicine. Former postdoctoral researchers Dr. Po-Yin Chu and Dr. Jessie M. English also contributed.

Amanda Siegfried | EurekAlert!
Further information:
http://www.utsouthwestern.edu

More articles from Studies and Analyses:

nachricht Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>