Navigation Links
Abnormal activation of a protein may explain deadly link between high salt intake and obesity

Bethesda, Md. (Sept. 19, 2011) Dietary salt intake and obesity are two important risk factors in the development of high blood pressure. Each packs its own punch, but when combined, they deliver more damage to the heart and kidneys than the sum of their individual contributions. Discovering the molecular mechanisms behind this lethal synergy has presented a challenge to scientists, but research led by Toshiro Fujita, MD, professor and chairman of the Department of Internal Medicine and chief of the Department of Nephrology and Endocrinology at the University of Tokyo, suggests that high dietary salt intake and obesity work together to trigger an abnormal activation of a cellular protein called Rac1.

How Obesity and a High-Salt Diet Team Up

Dr. Fujita's team studied the effects of a high-salt diet in rats bred to have high blood pressure and different levels of blood pressure sensitivity to salt. When obese "salt-sensitive" rats were fed a high-salt diet, the team found that Rac1 activated the mineralocorticoid receptor (MR) on the rats' kidney cells. This receptor is normally activated by the hormone aldosterone. When turned on, MR leads to the expression of a protein called epithelial sodium channel (ENaC) and an enzyme called the sodium pump. Both of these substances promote the reabsorption of salt, which causes the body to retain fluid and results in high blood pressure. This is the first time scientists have seen Rac1 usurp aldosterone's role in activating MR in the regulation of blood pressure. The protein's usual duties entail regulating an array of cellular events such as cell growth.

The team made the discovery when attempting to treat the obese, hypertensive rats with drugs designed to block MR activation and inhibit Rac1. When Rac1 inhibitors were successful in lowering the rats' blood pressure, the team knew they had discovered a mechanism by which obesity and a high-salt diet team up to wreak havoc on blood pressure and the kidneys.

Importance of the Findings

According to Dr. Fujita, the team's findings carry important implications for the treatment of hypertension. "Our data indicate that the Rac1-mediated pathway in the kidneys can be an alternative therapeutic target for salt-sensitive hypertension and salt-mediated kidney injury," he said. "Based upon our results, we can speculate that Rac1 in the kidneys regulates salt susceptibility of blood pressure, and that Rac1 inhibitors, as well as MR antagonists, may be effective in the treatment of salt-sensitive hypertension."


Contact: Donna Krupa
American Physiological Society

Related biology news :

1. Study finds chronic abnormal brain blood flow in Gulf War veterans
2. BMC awarded NIH grant to study brain abnormalities in former ELGANS patients
3. Early embryos can correct genetic abnormalities during development
4. Could ovarian stimulation cause an increase in oocyte chromosome abnormalities?
5. Electronic tracking system can improve follow-up after an abnormal Pap test
6. UT MD Anderson study ties abnormal cells in blood to lung cancer
7. Brain abnormalities in Parkinsons patients develop before symptoms occur
8. New chromosomal abnormality identified in leukemia associated with Down syndrome
9. Abnormal brain circuits may prevent movement disorder
10. New test can detect both genetic and chromosomal abnormalities in embryos
11. High carbon dioxide levels cause abnormally large fish ear bones
Post Your Comments:
(Date:11/12/2015)... CAMBRIDGE, Mass. , Nov. 12, 2015 /PRNewswire/ ... Broad Institute of MIT and Harvard for use ... chemical discovery information management tools. The partnership will ... share both biological and chemical research information internally ... tools will be used for managing the Institute,s ...
(Date:11/10/2015)... 10, 2015  In this report, the ... of product, type, application, disease indication, and ... report are consumables, services, software. The type ... biomarkers, efficacy biomarkers, and validation biomarkers. The ... diagnostics development, drug discovery and development, personalized ...
(Date:11/9/2015)... 2015  Synaptics Inc. (NASDAQ: SYNA ), the ... entry into the automotive market with a comprehensive and ... of consumer electronics human interface innovation. Synaptics, industry-leading touch ... the automotive industry and will be implemented in numerous ... , Japan , and ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... ... 24, 2015 , ... This fall, global software solutions leader SAP and AdVenture ... develop and pitch their BIG ideas to improve health and wellness in their schools. ... to win the title of SAP's Teen Innovator, an all-expenses paid trip to Super ...
(Date:11/24/2015)... 24, 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: ... the remaining 11,000 post-share consolidation (or 1,100,000 pre-share ... "Series B Warrants") subject to the previously disclosed ... 23, 2015, which will result in the issuance ... to the issuance of such shares, there will ...
(Date:11/24/2015)... 24, 2015 /CNW Telbec/ - ProMetic Life Sciences Inc. (TSX: ... Mr. Pierre Laurin , President and Chief Executive Officer ... upcoming Piper Jaffray 27 th Annual Healthcare Conference to ... 1-2, 2015. st , at 8.50am (ET) ... throughout the day. The presentation will be available live via ...
(Date:11/24/2015)... ... ... Whitehouse Laboratories is pleased to announce that it has completed construction on ... to basic USP 61, USP 62 and USP 51 testing specific to raw materials ... micro testing performed by one supplier. Management has formally announced that the ...
Breaking Biology Technology: