For one, people differ in how greatly exercise alters their blood sugar equilibrium, an effect demonstrated in a new study by researchers at Washington University School of Medicine in St. Louis and other institutions in the HERITAGE Family Study.

The divergence in exercise response allowed the researchers to identify regions on chromosomes 6, 7, and 19 that are linked to prediabetes. Their report appears in the June issue of Diabetologia.

Prediabetes is characterized by the body's elevated resistance to insulin, the hormone that regulates blood glucose levels and energy storage. The condition generally advances to type 2 diabetes as the pancreas works to secrete insulin to compensate for increased insulin resistance in the body's liver, muscle and fat cells. When the pancreas can no longer make enough insulin to keep blood sugar levels down in the normal range, clinically overt type 2 diabetes results.

"There's no question at all that prediabetes and type 2 diabetes have a genetic basis," says lead author Ping An, M.D., research assistant professor in genetics and biostatistics. "The rising incidence of type 2 diabetes makes it more and more important to locate the genes so they can lead to effective intervention and treatments."

Four hundred and forty-one nondiabetic, sedentary parents and offspring in 98 white and 90 black families were studied. Each participant put aside their inactive lifestyle for a 20-week, supervised program of aerobic exercise. Researchers made sophisticated measurements of insulin action and glucose metabolism at the start of the program and then again after it was done.

"At the end of the exercise program, the insulin sensitivity of the participants had improved overall--they needed to produce less insulin to handle the same amount of glucose intake," says An. "But the amount of improv
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Contact: Gwen Ericson
ericsong@wustl.edu
314-286-0141
Washington University School of Medicine
28-Jun-2005