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

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>