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 Real-time feedback helps save energy and water
08.02.2017 | Otto-Friedrich-Universität Bamberg

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>