Featured Research

from universities, journals, and other organizations

Ancient Enzyme Guides Healthy Eating In Mammals

Date:
April 29, 2005
Source:
Cell Press
Summary:
An ancient enzyme in the brains of mammals acts as an innate nutritionist of sorts, guiding them to make healthy choices about what to eat, according to new work published in the April issue of Cell Metabolism. The molecular mechanism is likely to be important in all mammals, including humans, that eat a varied diet comprised of meat and vegetables, the researchers said.

An ancient enzyme in the brains of mammals acts as an innate nutritionist of sorts, guiding them to make healthy choices about what to eat, according to new work published in the April issue of Cell Metabolism. The molecular mechanism is likely to be important in all mammals, including humans, that eat a varied diet comprised of meat and vegetables, the researchers said.

David Ron, of the New York University School of Medicine, and his colleagues found in mice that an enzyme known as GCN2 kinase sets off a cascade of events that relays information to the brain about the amino acid content of foods, enabling the animals to adjust their intake in favor of a more balanced meal. The same enzyme in yeast also acts as an amino acid sensor, earlier work has shown.

"This ancient pathway in mice recognizes drops in blood amino acid levels that occur following consumption of food with an imbalanced composition," said Ron. "That recognition culminates in a behavioral response that limits consumption of the imbalanced food and favors, by default, a more balanced diet."

The new findings confirm and extend a recent report by Dorothy Gietzen at the University of California, Davis, detailing the same pathway in rats.

Amino acids are the building blocks of proteins. While many of the 20 amino acids can be synthesized internally, eight "essential" amino acids must be obtained from food. Scientists have long known that omnivorous animals will consume substantially less of a meal lacking a single essential amino acid, in comparison to an otherwise identical meal that is nutritionally complete.

To explore the role of GCN2 kinase in this feeding behavior, the researchers inactivated the enzyme in the brains of mice. GCN2 kinase, known to be an important amino acid sensor, elicits a stress response by modifying a second protein called translation initiation factor 2 (eIF2a).

Mice without the normal complement of GCN2 in the brain failed to exhibit an aversion to imbalanced food, the researchers reported. The protein inactivation also led to a decline in modified eIF2a in a key part of the brain following consumption of an imbalanced meal.

The findings reveal that the ancient amino acid-sensing pathway affects feeding behavior by activating a brain circuit that biases consumption against imbalanced food sources, the researchers said.

While the findings are in mice, "there's no reason to believe that the same mechanism isn't at work in humans," Ron said. However, he suspects that cultural influences coupled with an instinctual drive to consume foods rich in calories might often override the amino acid gauge that would otherwise promote a balanced diet.

###

The researchers include Anne-Catherine Maurin, Cιline Jousse, Julien Averous, Laurent Parry, Alain Bruhat, Yoan Cherasse,and Pierre Fafournoux of the Institut National de la Recherche Agronomique de Theix in Saint Genθs-Champanelle, France; and Huiqing Zeng, Yuhong Zhang, Heather P. Harding, and David Ron of the Skirball Institute of Biomolecular Medicine at New York University School of Medicine in New York, New York. This work was supported by an NIH grant.

Anne-Catherine Maurin, Cιline Jousse, Julien Averous, Laurent Parry, Alain Bruhat, Yoan Cherasse, Huiqing Zeng, Yuhong Zhang, Heather P. Harding, David Ron, and Pierre Fafournoux: "The GCN2 kinase biases feeding behavior to maintain amino acid homeostasis in omnivores"

Publishing in Cell Metabolism, Volume 1, Number 4, April 2005, pages 273-277. www.cellmetabolism.org


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Cite This Page:

Cell Press. "Ancient Enzyme Guides Healthy Eating In Mammals." ScienceDaily. ScienceDaily, 29 April 2005. <www.sciencedaily.com/releases/2005/04/050428183259.htm>.
Cell Press. (2005, April 29). Ancient Enzyme Guides Healthy Eating In Mammals. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2005/04/050428183259.htm
Cell Press. "Ancient Enzyme Guides Healthy Eating In Mammals." ScienceDaily. www.sciencedaily.com/releases/2005/04/050428183259.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) — Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) — At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) — The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. 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