Studying glucagon action in the brain may lead to new diabetes therapies

Increasing the action of glucagon in the brain may help scientists develop new ways for treating diabetes, according to a new study.
Glucagon is a hormone secreted by pancreatic alpha cells in response to low blood sugar levels. It causes blood sugar levels to rise, but this increase is only temporary with blood sugar levels soon returning to normal.
According to researchers at the Toronto General Research Institute, the decrease in blood sugar is believed to occur through glucagon action in the hypothalamus area of the brain, which directs a large number of important functions in the body.
In people with diabetes, however, glucagon’s temporary rise in blood sugar is impaired as either not enough insulin is present or the body is less able to respond to insulin. As a result, blood sugar levels remain elevated.
In experimental models of obesity and diabetes, the team at TGRI found that resistance to glucagon in the brain leads to spikes in blood sugar levels .
However, they also discovered that direct stimulation of the protein kinase A signalling pathways (PKA) in the brain bypasses this resistance and lowers blood sugar .
The scientists, led by diabetes and obesity research expert Dr. Tony Lam, said the findings pave the way for investigation of treating diabetes and obesity by increasing glucagon action in the brain .
“Drugs that aim to increase glucagon action in the brain and/or block glucagon action in the liver could regulate sugar levels in diabetes,” Dr. Lam explained.
“I believe that down the road, treating diabetes with glucagon therapy will be equally as effective as insulin therapy .”
The study, entitled “Hypothalamic glucagon signalling inhibits hepatic glucose production” was published in the online edition of the journal Nature Medicine .