The aim of the project was to find out how the healthy body regulates glucose concentrations in the blood.
Scientists have known for a long time that glucose is regulated with the help of hormones in the pancreas, which is to say that pancreatic beta cells produce insulin, which reduces sugar levels, and that alpha cells produce glucagon, which boosts them. This glucose balance must be kept within a very narrow interval, and we need both insulin and glucagon to remain in good health.
"A person with low blood sugar levels feels poorly and faint; a person with excessively high blood sugar levels gets diabetes," says Per-Olof Berggren, professor of experimental endocrinology at Karolinska Institutet and the leader of this study.
Much more is known about insulin secretion than glucagon secretion, and so Professor Berggren's team focused on the latter. They discovered that alpha cells also secreted glutamate, which facilitates glucagon release and makes it more efficient.
The scientists are working on the hypothesis that when glucose levels are raised in a healthy person, the beta cells become active and start to release insulin, which reduces sugar concentrations in the blood, upon which the alpha cells then start to secrete glucagon and glutamate. In this context, glutamate acts as a positive signal that tells the alpha cells that it is time to accelerate the production of glucagon to prevent glucose levels from falling too low.
"It's this signal pathway that is our discovery," says Professor Berggren. "This interaction between beta cells and alpha cells is crucial for normal blood sugar regulation."
The discovery also means that when the beta cells fail to produce insulin properly, as is the case in diabetes, the alpha cells' signal path is also blocked, which upsets the glucose balance even more. The team hope that their discovery of the signal pathway will eventually give new impetus to clinical diabetes research.
"Maybe we'll be able to achieve better blood sugar regulation in diabetes patients if we target more the glucagon/glutamate rather than just the insulin", says Professor Berggren.
Publication: 'Glutamate is a positive autocrine signal for glucagon release'. Authors: O Cabrera, MC Jaques-Silva, S Speier, S-N Yang, M Köler, A Fachado, E Vieira, JR Zierath, R Kibbey, DM Berman, NS Kenyon, C Ricordi, A Caicedo and P-O Berggren. Cell Metabolism, 4 June 2008.
For further information, please contact:Professor Per-Olof Berggren,
Katarina Sternudd | idw
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
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...
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...
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...
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....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences