People with diabetes who produce little or no insulin, which helps process sugar in the blood, often have to inject themselves with insulin several times a day. An experimental therapy that triggers the body to release proteins like insulin when needed may one day allow diabetics to say good-bye to insulin injections.

A new type of treatment involves infecting a person with a harmless virus that would carry insulin genes to cells, causing them to produce clusters of insulin that would be stored in the cells. When a burst of insulin was needed to process blood sugar, such as during meals or after exercise, the person would either swallow a pill or place a dissolving tablet under the tongue. Molecules in this medication would break up the insulin clusters in cells and cause insulin to be secreted.

Besides making it easier and more convenient to control diabetes, the same process could also be used to treat other conditions, such as cancer-related pain. Rather than insulin, however, the system would release the body's natural painkillers called endorphins. The treatment is not ready for tests in people yet, although the results of laboratory and animal tests are promising. Shortly after diabetic mice were given the oral medication, their cells produced enough insulin to keep their blood sugar under control. The mice in the study were implanted with cells engineered to produce insulin. The amount of insulin released depended on how large a dose of medication the mice were given.

Science February 4, 2000;287:816-817, 826-830.