The traditional prescriptions for a healthy lifesensible diet, exercise and weight controlextend life by reducing signaling through a specific pathway in the brain, according to Howard Hughes Medical Institute researchers who discovered the connection while studying long-lived mice.
They said their findings underscore the importance of maintaining a healthy lifestyle and may also offer promising research directions for understanding and treating diabetes and Alzheimers disease.
Howard Hughes Medical Institute investigator Morris F. White and his colleagues published their findings in the July 20, 2007, issue of the journal Science. Akiko Taguchi and Lynn Wartschow in Whites laboratory in the Division of Endocrinology at Childrens Hospital Boston and Harvard Medical School were co-authors of the research article.
In their experiments, the researchers sought to understand the role of the insulin-like signaling pathway in extending lifespan. This pathway governs growth and metabolic processes in cells throughout the body. The pathway is activated when insulin and insulin-like growth factor-1 switch on proteins inside the cell called insulin receptor substrates (Irs).
Other researchers had shown that reducing the activity of the pathway in roundworms and fruitflies extends lifespan. Despite those tantalizing clues, White said, The idea that insulin reduces lifespan is difficult to reconcile with decades of clinical practice and scientific investigation to treat diabetes.
In fact, based on our work on one of the insulin receptor substrates, Irs2, in liver and pancreatic beta cells, we thought more Irs2 would be good for you, said White. It reduces the amount of insulin needed in the body to control blood glucose, and it promotes growth, survival and insulin secretion from pancreatic beta cells.
In earlier work, the researchers had found that knocking out both copies of the Irs2 gene in mice reduces brain growth and prod
Contact: Jennifer Michalowski
Howard Hughes Medical Institute