Researchers have long puzzled over what causes the body to turn against itself in type 1 diabetes, an autoimmune disease that destroys insulin-secreting cells in the pancreas. Now, two studies suggest that insulin, a hormone that regulates blood sugar concentrations, may itself be to blame.
Insufficient amounts of insulin clearly lead to the symptoms of type 1 diabetes, but researchers haven't known whether the hormone directly sets the immune system on its course to creating the disease. Other molecules, such as the enzyme glutamic acid decarboxylase, may also play pivotal roles in this process, and any of these could become targets for new drugs.
"We know there are many targets in type-1 diabetes," says George Eisenbarth of the University of Colorado Health Sciences Center in Denver. "The fundamental question is whether any one target is more important than any other."
Eisenbarth and his colleagues worked with mice genetically predisposed to develop type 1 diabe