Gene for Insulin Trigger Isolated, Important Step in Diabetes Research
NEW YORK (AP) _ The discovery of the genetic blueprint for an insulin ″trigger″ that plays a role in diabetes could ultimately lead to new treatments and custom- designed drugs to treat the disease, which afflicts an estimated one in 20 Americans, a researcher says.
In a report published today, researchers announced the discovery of the gene that guides the production of a molecule called the insulin receptor, which allows human cells to respond to insulin.
The receptor, located on the surface of human cells, triggers cell changes when it detects insulin outside the cell.
″It is probably the most important hormone receptor in the body″ and is found on ″basically all cells in the human body,″ said one of the discoverers of the gene, Axel Ullrich of Genentech Inc., in South San Francisco.
″In the long run, this receptor and other types of receptors will be very important in the development of new kinds of drugs,″ he said. ″We can probably use the computer to design new drugs that will have an effect interacting with the receptor.″
Ullrich said the new findings might make possible prenatal diagnosis of certain forms of diabetes in which patients have a normal supply of insulin but appear to have defective insulin receptors that are not capable of recognizing the insulin.
Ullrich and others from Genetech, working in collaboration with Dr. Ora Rosen of Memorial Sloan-Kettering Cancer Center in New York, reported their discovery in a report published today in Nature, a respected British scientific journal.
Ms. Rosen said the finding was not likely to help anyone with diabetes in the near future but does provide useful tools for studying the illness.
″The more you know about how insulin works and how insulin receptors work, the more ideas you get about what goes wrong in patients with diabetes,″ she said.
Diabetes is a poorly understood illness in which the body’s ability to convert sugars and starches into energy is disrupted or impaired. Insulin and the insulin receptors help to regulate that energy production.
The U.S. Public Health Service estimates that various forms of the disease afflict approximately 10 million people in the United States - or one in every 20 Americans.
In the Nature report, the scientists said they also found an intriguing resemblance between the insulin receptor gene and a family of cancer genes called the src genes (pronounced ″sarc″).
That had been expected, because the insulin receptor was known to share some properties with another receptor closely linked to a cancer gene, Ms. Rosen said.
Both the insulin receptor and the other receptor, which recognizes a substance called epidermal growth factor, are involved in the growth and reproduction of cells.
Cancer is characterized in part by chaotic, unrestrained growth, such as is seen in a tumor. Researchers have theorized that some alteration or defect in growth-related receptors could be responsible.
Receptors of various types reside on the surface of human cells. Each is designed to recognize a specific substance. Whenever such a substance comes into contact with its corresponding receptor, it binds to the receptor and the receptor begins sending signals to the inside of the cell.