Brain May Control Type 2 Diabetes
Altering Single Gene in the Brain of Mice Cures Abnormal Sugar Metabolism Seen in Type 2 Diabetes
Nov. 12, 2003 -- The key to curing type 2 diabetes may be in
our heads, or at least in the heads of mice. A new study shows that altering a
single gene in the brains of obese mice bred to have type 2 diabetes helped
them completely normalize blood sugar levels.
Researchers say that it's the first study to show that glucose
control may be regulated by the brain. If further research confirms these
results, it could open a whole new approach to treating type 2 diabetes.
People with type 2 diabetes are unable to regulate their blood
sugar (glucose) levels normally because their bodies have become resistant to
insulin, which is the hormone responsible for controlling glucose in the
Researchers say that obesity is thought to lead to decreased
insulin sensitivity and then to type 2 diabetes. But this study suggests that
obesity and type 2 diabetes may both be caused by the same genetic defect in
Brain Gene Provides Glucose Control
In the study, published in the November issue of
Diabetes, researchers looked at the effect of manipulating a gene in the
brain known as POMC in mice bred to be obese with type 2 diabetes.
Previous studies have shown that POMC production is reduced in
the brains of obese and diabetic mice. People with mutations in this gene are
also obese and diabetic. But because many genes are implicated in obesity and
diabetes, it's not clear which genes, if any, play a role in regulating glucose
The study showed that when the activity of POMC was increased
through genetic engineering, the mice reduced their food intake slightly and
lost some weight.
"But the surprising part was that the effect on glucose
regulation was not partial," says researcher Charles V. Mobbs, PhD,
assistant professor at the Fishberg Neurobiology of Aging Laboratories at the
Mount Sinai School of Medicine in New York City, in a news release. "Even
though these mice remained obese, their glucose levels were completely
Those findings showed that the dramatic improvement in glucose
control and regulation was not related to the weight loss.
New Direction for Diabetes Research
Mobbs says these new results suggest this perception of a
cause-and-effect relationship between obesity and glucose control might
sometimes be wrong.
"It appears that both conditions can be caused by the same
defects, impairments in the production, processing, or responsiveness to POMC
gene products," says Mobbs.
Mobbs says it's still too soon to rule out a role of obesity in
glucose regulation, but drugs that mimic the effects of the POMC gene may
eventually be useful for people who developed diabetes due to aging or as the
result of damage to the hypothalamus, which might affect the body's own POMC
He says drugs that mimic POMC are already being studied for the
treatment of obesity, but it may turn out that these drugs will be even more
effective in treating type 2 diabetes.
But until those drugs are available, he says diet and exercise
are the best way to control glucose levels and type 2 diabetes.