MONDAY, March 16 (HealthDay News) -- Mice that overexpress a protein that normally increases in muscle after exercise have improved glucose tolerance and insulin sensitivity and do not become obese even after eating a high-fat diet, according to a study published online March 5 in Endocrinology.
Yasuhide Fukatsu, from Kobe University Graduate School of Medicine in Japan, and colleagues analyzed changes in gene expression in the skeletal muscle of mice in response to exercise. After finding a twofold to threefold increase in heparin-binding epidermal growth factor-like growth factor (HB-EGF, also known as diphtheria toxin receptor) expression, they generated mice overexpressing HB-EGF specifically in skeletal muscle.
The researchers found that the mice had a higher respiratory quotient, indicating a preference for carbohydrate rather than fat as an energy source. They also had improved glucose tolerance, insulin sensitivity, and glucose uptake by skeletal muscle. When fed a high-fat diet, the mice were largely resistant to developing obesity, hepatic steatosis and insulin resistance.
"In the present study, we have revealed a potential role for HB-EGF in energy homeostasis by showing that its overexpression in muscle of transgenic mice increases whole-body carbohydrate utilization, glucose tolerance, and insulin sensitivity," Fukatsu and colleagues conclude. "Given that this growth factor is a key bioactive molecule up-regulated in contracting muscle, which handles a large proportion of incoming glucose, our results might provide important insight into the molecular basis of exercise treatment for various pathological conditions associated with insulin resistance."
Abstract
Full Text (subscription or payment may be required)