Featured Research

from universities, journals, and other organizations

Exploding Eggs And Rare Human Disorder Help Explain Water Regulation

Date:
July 19, 2001
Source:
Johns Hopkins Medical Institutions
Summary:
Acting on a scientific hunch, Hopkins medical sleuths set out to find individuals with an extremely rare disorder affecting their ability to internally process water. Using international blood banks, the investigators identified two such persons, confirming their belief that the absence of a certain protein interferes with the body's ability to regulate its water levels.

Acting on a scientific hunch, Hopkins medical sleuths set out to find individuals with an extremely rare disorder affecting their ability to internally process water. Using international blood banks, the investigators identified two such persons, confirming their belief that the absence of a certain protein interferes with the body's ability to regulate its water levels. The finding, reported in the July 19 issue of the New England Journal of Medicine, provides insight into how the kidney works.

"This is the first study to show that the protein called aquaporin-1 has a clear role in the normal function of the kidney," says Landon King, M.D., an assistant professor of pulmonary medicine and lead author of the study. "Aquaporin-1 is required for the kidney to concentrate urine, a fundamental process for all mammals."

The study showed that individuals deficient in the protein have a limited ability to concentrate urine, or, in other words, to reabsorb water through their kidneys. This is essential for maintaining healthy water levels in the body. The finding may help doctors develop treatments for diseases such as diabetes insipidus, an ailment that inhibits reabsorption of water causing frequent urination and emaciation.

Until 10 years ago, scientists didn't know how cells regulate water, surprising since this task is fundamental to life. Water makes up 70 percent of the human body, and while certain cells need to absorb water quickly, other cells are relatively impermeable to water. Then, roughly 10 years ago, Peter Agre, M.D., a Hopkins professor of biochemistry, stumbled upon an unknown protein lodged in the plasma membrane of red blood cells and kidney tubules. After expressing the protein in frogs' eggs, the scientists discovered that the eggs exploded when immersed in water because they absorbed the liquid much faster than normal. Agre named the protein aquaporin because it acted as a pore or water channel through which fluids flow in and out of the membrane.

Since the exploding frog eggs, scientists have identified 10 aquaporin proteins in the more water-permeable parts of the body -- the moist surface tissues of the alveoli in the lung, tubules in the kidneys, and tear glands, to name a few. But researchers wondered whether they could find any people with missing or defective aquaporin proteins. To accomplish their goal, Agre and pulmonologist Landon King turned to international blood banks and identified six families with a deficiency in aquaporin-1(AQP1). After tracking down two of the individuals – a 37-year-old woman from North Carolina and a 57-year old woman from France – and depriving them of water for 24 hours under close monitoring, King determined that they have a limited ability to concentrate urine.

Surprisingly however, the individuals did not have more serious health issues, since AQP1 is involved in transporting water not only in the kidneys but in a number of other organs, including the lungs and pancreas. "We believe that these people have some form of compensation that helps to mitigate the severity of the problem and most likely developed these compensatory mechanisms in the womb," says King. "If a person suddenly developed a deficiency in AQP1 without these compensatory mechanisms, they are much more likely to have severe health problems."

In addition to King and Agre, other authors include Michael Choi, M.D., from Johns Hopkins, as well as Jean-Pierre Cartron, Ph.D., and Pedro Fernandez, M.D., from the University of Pennsylvania. The National Institutes of Health, the Cystic Fibrosis Foundation and the National Center for Research Sources funded the study.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Exploding Eggs And Rare Human Disorder Help Explain Water Regulation." ScienceDaily. ScienceDaily, 19 July 2001. <www.sciencedaily.com/releases/2001/07/010719080735.htm>.
Johns Hopkins Medical Institutions. (2001, July 19). Exploding Eggs And Rare Human Disorder Help Explain Water Regulation. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2001/07/010719080735.htm
Johns Hopkins Medical Institutions. "Exploding Eggs And Rare Human Disorder Help Explain Water Regulation." ScienceDaily. www.sciencedaily.com/releases/2001/07/010719080735.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins