Texas Researchers Hopeful They Can Eliminate the Need For Insulin Therapy

Research conducted at the University of Texas Southwestern Medical Center raises the exciting prospect of eliminating the need for insulin in type 1 diabetics by "turning off" the hormone glucagon, which plays a major role in blood sugar regulation.

Like insulin, glucagon is a hormone secreted by the pancreas. Glucagon has the opposite effect of insulin, increasing blood glucose levels rather than lowering them. The pancreas releases glucagon when blood sugar is low, causing the liver to release glucose into the blood stream, and stimulating the release of insulin.

Glucagon prevents low blood sugar in healthy people, but causes high blood sugar in people with type 1 diabetes, whose pancreas can't produce enough insulin to counteract its effect. A synthetic version of glucagon is used to treat severe low blood sugar, or hypoglycemia, in diabetics in emergency situations.

The UT Southwestern researchers genetically altered laboratory mice so that they lacked working glucagon receptors and couldn't react to glucagon. They then gave the mice the glucose tolerance test used to diagnose diabetes. Mice with normal insulin levels but non-working glucagon receptors responded normally to the test.

When their insulin-producing islet cells were destroyed and they lacked both insulin and the ability to use glucagon, they were still able to stabilize their blood sugar, again testing normally. Blocking the action of glucagon essentially made insulin unnecessary for the mice – despite the lack of both glucagon and insulin, the mice did not develop diabetes.

"We've all been brought up to think insulin is the all-powerful hormone without which life is impossible," says researcher and professor of internal medicine Dr. Roger Unger, "But that isn't the case. This doesn't mean that insulin is unimportant – it's essential for normal growth and development. But in adulthood, at least with respect to glucose metabolism, the role of insulin is to control glucagon. If you don't have glucagon, then you don't need insulin."

Insulin injections have been the treatment of choice for type 1 diabetes since its introduction in 1922. But insulin is a treatment, not a cure, and can't restore normal glucose tolerance as blocking the glucagon receptors did in the laboratory mice. It now appears that insulin's benefit results from its suppression of glucagon, and that the blocking of glucagon action restores glucose tolerance to normal.

In the next all-important step, the researchers will be studying the mechanism behind the results to determine how to turn off the glucagon receptors in humans. "If these latest findings were to work in humans, injected insulin would no longer be necessary for people with type 1 diabetes," states Dr. Unger, "If diabetes is defined as restoration of glucose homeostasis to normal, then this treatment can perhaps be considered very close to a cure."

Lynn blogs about news and views of interest to diabetics at longactinginsulin.com. Check out the blog for updates on the latest diabetes research, and get a $10 off prescription coupon for Lantus SoloSTAR long acting insulin pens.