Discovery of new signal pathway important to diabetes research

Scientists at Karolinska Institutet in Sweden and Miami University have discovered that cells in the pancreas cooperate – signal – in a way hitherto unknown. The discovery can eventually be of significance to the treatment of diabetes.

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.

Source: Karolinska Institutet

Related stories:

Why HIV treatment makes people so susceptible to heart disease and diabetes
Clinicians have known for some time that people treated for HIV also become much more susceptible to diabetes and heart disease. A study by scientists at Sydney's Garvan Institute of Medical Research has now shown some of the reasons why – enabling better patient management and monitoring.
Diabetes ABCs 123s
Here is a statistic from the American Diabetes Association that caught my attention: "If current trends continue, one out of three Americans and one in two minorities born in 2000 will develop diabetes in their lifetime."
Moderate use averts failure of type 2 diabetes drugs in animal model
Drugs widely used to treat type 2 diabetes may be more likely to keep working if they are used in moderation, researchers at Washington University School of Medicine in St. Louis have found in a study using an animal model.
Feel-good foods: What you eat can affect your mood
Chocolate cake is a popular home remedy for depression, but it comes with some unwelcome side effects. Sweet treats don't just pack on the pounds; they give us a sugar high that's inevitably followed by a demoralizing crash.
Link between sleep and diabetes
We hadn't done this before. Two of us - one from our hospital's sleep center and the other from our diabetes program - were both listening intently to a teleconference on sleep apnea and diabetes. What does one have to do with the other? Perhaps plenty, according to research in both fields.
Researchers continue to find genes for type 1 diabetes
Genetics researchers have identified two novel gene locations that raise the risk of type 1 diabetes. As they continue to reveal pieces of the complicated genetic puzzle for this disease, the researchers expect to improve predictive tests and devise preventive strategies.
A breakthrough, then a surge, in stem cell research
Less than a year after a Wisconsin team helped discover a major alternative to human embryonic stem cells, the Madison scientists say more than 800 labs have begun using the approach, suggesting that many stem-cell researchers are starting to move beyond controversial embryonic sources for their work.
Too many calories send the brain off kilter
An overload of calories throws critical portions of the brain out of whack, reveals a study in the October 3rd issue of the journal Cell, a Cell Press publication. That response in the brain's hypothalamus—the "headquarters" for maintaining energy balance -- can happen even in the absence of any weight gain, according to the new studies in mice.

News discussion:

Medicine & Health news