Navigation Links
Researchers may have found why women have an edge on salt-sensitive hypertension
Date:1/28/2009

AUGUSTA, Ga. Researchers may have found why women have an edge in keeping a healthier balance between the amount of salt they eat and excrete - at least before reaching menopause.

Premenopausal women are known to have fewer problems with salt-sensitive hypertension and hypertension in general, but afterward their risks are essentially the same as men, says Dr. David Pollock, renal physiologist in the Vascular Biology Center at the Medical College of Georgia.

The reason appears to be related to female hormones and a new-found role of a cell receptor previously thought to be only harmful, he and colleagues report in the February issue of Hypertension.

Their finding points to the need for gender studies on how these endothelin A, or ETA, receptors work in the blood vessels and tubules of the kidney. They also may help explain the swelling that occurs in some patients taking powerful new ETA antagonists, which are in use for pulmonary hypertension and under study for conditions such as diabetic nephropathy and uncontrolled hypertension. These antagonists block the action of ETA receptors which are believed to raise blood pressure and help reshape blood vessels into thick, rigid pipes.

ETA receptors have been considered the evil sibling of endothelin B, or ETB, receptors, which are believed to stimulate nitric oxide production, blood vessel relaxation and salt excretion, Dr. Pollock says. "Normally the ETB receptor system is a decision maker about how much sodium to keep and how much to excrete."

As with Dr. Pollock's rats, people with ETB receptor problems are said to be salt sensitive. "We know from other studies we have done that this endothelin B receptor is critical to keeping you from becoming hypertensive when you eat salt," Dr. Pollock says.

The body gets the sodium it needs from food and a healthy kidney should be able to eliminate excess from a high-salt diet so there is always a balance between what is consumed and excreted. Salt-sensitive hypertension means kidneys hold onto too much salt. When the kidneys realize the blood pressure is getting too high they try to get rid of salt. If they can't, in an ironic twist, blood pressure goes even higher to help literally force salt out of the kidneys. That approach eventually works but over time the high-pressure pounding away at blood vessels can cause heart attack, stroke and/or kidney failure, the type of end stage organ damage associated with hypertension, Dr. Pollock says.

In female rats at least, ETA receptors are less prone to reduce blood flow to the kidneys compared to males and actually increases sodium excretion without increasing blood pressure. Researchers found this by studying a rat missing the ETB receptor. When they gave the animals the protein endothelin to see if it could help them excrete salt without an ETB receptor, males did not respond but females experienced a significant improvement. When they took out the ovaries, female rats responded more like the males. Dr. Pollock says estrogen seems to drive the beneficial action of the ETA receptor. Additionally, researchers found stimulation of the ETB receptor increased urine output and sodium excretion in both sexes, suggesting that it was not a player in the differing responses between males and females.

"According to what we know, blocking the ETA receptor is a good thing and blocking the ETB receptor is a bad thing," Dr. Pollock says. Their findings indicate that actually may depend on whether you are a male or female rat and point to the need for human studies, he adds.

MCG researchers plan more laboratory studies to more specifically determine what different receptor subtypes are doing in the kidney's tubules and vasculature while colleagues at the University of Edinburgh in Scotland are beginning studies to look at how ETA receptor blockers impact sodium excretion in humans.


'/>"/>

Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
Source:Eurekalert  

Related biology news :

1. Researchers identify new function of protein in cellular respiration
2. Natural brain substance blocks weight gain in mice, UT Southwestern researchers discover
3. Researchers identify a cell type that limits stroke damage
4. Researchers iron out new role for serotonin
5. Researchers identify 4 genetic hotspots associated with psoriasis
6. Researchers genetically link Lou Gehrigs disease in humans to dog disease
7. Texas Medical Center researchers win collaborative grants
8. Researchers describe protease inhibitor that may aid in diabetic retinopathy treatment
9. Researchers examine developing hearts in chickens to find solutions for human heart abnormalities
10. JDRF-funded researchers discover proteins regulating human beta cell replication
11. Researchers to use K-States BSL-3 Lab for $1 million study of fungus threatening wheat crops
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Researchers may have found why women have an edge on salt-sensitive hypertension
(Date:5/16/2016)... --  EyeLock LLC , a market leader of iris-based ... IoT Center of Excellence in Austin, Texas ... embedded iris biometric applications. EyeLock,s iris authentication ... with unmatched biometric accuracy, making it the most proven ... platform uses video technology to deliver a fast and ...
(Date:4/28/2016)... India , April 28, 2016 ... Infosys (NYSE: INFY ), and Samsung SDS, a ... that will provide end customers with a more secure, ... services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ) , ... services, but it also plays a fundamental part in enabling ...
(Date:4/19/2016)... The new GEZE SecuLogic access ... "all-in-one" system solution for all door components. It can ... door interface with integration authorization management system, and thus ... minimal dimensions of the access control and the optimum ... offer considerable freedom of design with regard to the ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 2016 Houston Methodist Willowbrook Hospital has ... Association to serve as their official health care ... Willowbrook will provide sponsorship support, athletic training services, ... coaches, volunteers, athletes and families. "We ... Association and to bring Houston Methodist quality services ...
(Date:6/23/2016)... , June, 23, 2016  The Biodesign Challenge ... envision new ways to harness living systems and biotechnology, ... Art (MoMA) in New York City ... 130 participating students, showcased projects at MoMA,s Celeste Bartos ... Paola Antonelli , MoMA,s senior curator of architecture and ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... STACS DNA ... Technical Leader at the Arkansas State Crime Laboratory, has joined STACS DNA as a ... STACS DNA team,” said Jocelyn Tremblay, President and COO of STACS DNA. “In further ...
(Date:6/23/2016)... 2016  Blueprint Bio, a company dedicated to identifying, ... community, has closed its Series A funding round, according ... "We have received a commitment from Forentis Fund ... to meet our current goals," stated Matthew Nunez ... to complete validation on the current projects in our ...
Breaking Biology Technology: