Insulin reverses elderly muscle loss

GALVESTON, Texas, Sept. 28 (UPI) -- Insulin may help turn back the clock on elderly muscle loss, U.S. researchers said.

The study, published in Diabetologia, said giving insulin intravenously and increasing the blood insulin levels to the same amount produced after a meal stimulates protein synthesis and muscle growth in young people but not in older people. However, giving seniors double the insulin they would normally produce after eating stimulated muscles as it does in young people.

"These were older subjects with perfect glucose tolerance," senior author Dr. Elena Volpi of the University of Texas Medical Branch at Galveston says in a statement. "So what we have identified is a novel kind of insulin resistance that's not related to sugar control."

The researchers worked with 14 elderly volunteers to examine the response of thigh muscle to the two different blood insulin levels infused into the thigh's main artery.

Catheters inserted in the femoral artery and vein of each subject allowed calculation of blood flow and muscle protein synthesis.

Muscle protein was also gauged using muscle biopsies, the researchers say.