Life-extending Protein Keeps Blood Sugar in Control

A protein that extends lifespan in yeast, worms, and flies keeps blood sugar under control in mice.

The findings suggest therapeutic interventions for the prevention and treatment of metabolic disorders, such as type 2 diabetes, which frequently arise with age, the researchers said.

The team found that mice with an excess of the protein Sirt1 in cells of the pancreas have improved glucose tolerance and enhanced insulin secretion in response to glucose. Glucose is the principal circulating sugar in the blood and the major energy source of the body.

"Mice with an increased amount of Sirt1 show a better response to high blood glucose levels that regularly occur after eating sweets, such as cookies or cakes," said Shinichiro Imai of Washington University School of Medicine. "The mice respond fast to high glucose by raising insulin levels, clearing the blood of the circulating sugar."

"Under normal feeding conditions, when glucose levels are lower, the mice with elevated Sirt1 appear normal," Imai added. "This is good news, suggesting that therapies designed to manipulate the amount of Sirt1 might improve insulin response in those with type 2 diabetes without causing other problems."

The researchers found that Sirt1 is present in pancreas cells that secrete insulin hormone. Mice genetically modified to have an excess of Sirt1 in b cells of the pancreas had improved glucose tolerance and enhanced insulin secretion in response to glucose.

The altered mice maintained their improved b cell function with age, they reported. Further analyses found that Sirt1 regulates genes involved in insulin secretion by b cells.

"Together, these results establish that an increase dosage of Sirt1 has beneficial effects on mammalian physiology," Imai said. "Our findings also provide new insight into the physiological and molecular functions of Sirt1 in glucose metabolism and suggest therapeutic interventions for the prevention and treatment of diabetes and other age-associated metabolic disorders."

Moynihan et al.: "Increased Dosage of Mammalian Sir2 in Pancreatic ß Cells Enhances Glucose-Stimulated Insulin Secretion in Mice" Publishing in Cell Metabolism, Vol. 2, August 2005, pages 105-117. DOI 10.1016/j.cmet.2005.07.001 https://www.cellmetabolism.org

================================

DID YOU KNOW:
Researchers Monitor the Autoimmune Inflammation of the Pancreas: Investigators from Joslin diabetes Center describe a magnetic resonance imaging (MRI) strategy to non-invasively monitor autoimmune inflammation in the pancreas of a living animal. The researchers were able to track the pancreatic islet infiltrate that accompanies autoimmune diabetes in mice, and follow the resolution of inflammation after successful reversal of diabetes with therapy.

==============================

Advertisement

Byetta™ (exenatide) injection
New BYETTA mimics natural physiology for self-regulating glycemic control.
www.BYETTA.com