Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Joslin study pinpoints role of insulin on glucagon levels

08.04.2009
Researchers at the Joslin Diabetes Center have shown for the first time that insulin plays a key role in suppressing levels of glucagon, a hormone involved in carbohydrate metabolism and regulating blood glucose levels.

The study helps in the understanding of why those with diabetes have high blood glucose levels and could lead to development of a drug aimed at targeting glucagon levels.

"This is a very important finding because until now scientists have only speculated that insulin may be involved in keeping glucagon levels in check," said Rohit N. Kulkarni, M.D., Ph.D., Principal Investigator in the Joslin Section on Cellular and Molecular Physiology and senior author of the study published today in the April issue of Cell Metabolism.

Produced by the alpha cells in the pancreas, glucagon acts on the liver to help raise blood glucose when it becomes low. It has the opposite effect on the liver as insulin, which is released from pancreatic beta cells to lower blood glucose when it is high. In a healthy individual, the two counter each other to keep blood glucose levels balanced. In individuals with long-standing type 1 or type 2 diabetes, inappropriate glucagon secretion can increase the chances of hypoglycemia (low blood glucose levels) and can interfere with insulin therapy.

The finding suggests that for people with either type 1 or type 2 diabetes, a therapeutic approach could be developed to target insulin receptors or proteins in alpha cells in order to suppress glucagon secretion.

In addition, the research may also help in the understanding of why patients with type 1 diabetes in particular, who are required to inject insulin on a regular basis, are at risk for hypoglycemia. It was thought that this increased risk was linked in some way to insulin receptors in the alpha cells, an idea that today's study suggests is in fact the case, Dr. Kulkarni explained.

"This gives us some insight into the cause of hypoglycemia, the most common complication in patients with type 1 diabetes," he said. "Injecting insulin leads to a decrease in blood glucose. If it starts to go too low, glucagon normally kicks in to prevent hypoglycemia. But, what happens in diabetes is the alpha cells become desensitized by repeated insulin injections over many years and they start to behave abnormally. We believe this is linked to insulin receptor function."

In the study, Dr. Kulkarni and his team created a genetically engineered mouse model in which pancreatic alpha cells – those that secrete glucagon – were modified so that they did not contain insulin receptors. The idea was to explore the role of insulin in regulating glucagon secretion.

The modified mice exhibited elevated glucagon levels and also showed impaired glucose tolerance, as is seen in diabetes.

"This is the first genetic model wherein we provide definitive proof that insulin is able to suppress glucagon in mammals," Dr. Kulkarni said. "The next step is to identify the specific proteins in alpha cells that could be targeted to suppress glucagon secretion."

The paper concludes that the findings indicate there is a significant role for insulin signaling in the regulation of alpha cell functioning in both normal and hypoglycemic conditions and provide direct genetic evidence for a key role for insulin receptors in the modulation of pancreatic alpha cell function.

The study was funded in part by the American Diabetes Association, the Swiss National Science Foundation, the National Institutes of Health and the European Union.

Also contributing to the research were Dan Kawamori, Amarnath J. Kurpad, Jiang Hu, Chong Wee Liew and Judy L. Shih, all of Joslin; Eric L. Ford and Kenneth S. Polonsky, both of Washington University School of Medicine; Pedro L. Herrera, University of Geneva Medical School; and Owen P. McGuinness, Vanderbilt University School of Medicine.

About Joslin Diabetes Center

Joslin Diabetes Center is the world's preeminent diabetes research and clinical care organization. Joslin is dedicated to ensuring people with diabetes live long, healthy lives and offers real hope and progress toward diabetes prevention and a cure for the disease. Founded in 1898 by Elliott P. Joslin, M.D., Joslin is an independent nonprofit institution affiliated with Harvard Medical School. For more information about Joslin, call 1-800-JOSLIN-1 or visit www.joslin.org.

Kira Jastive | EurekAlert!
Further information:
http://www.joslin.harvard.edu
http://www.joslin.org

More articles from Studies and Analyses:

nachricht Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>