Fat Hormone May Contribute To Longevity
(Nov. 23, 2007) — Both humans and mice that manage to live to a ripe, old age show a clear change in their glucose metabolism, but it's unclear whether this change alone can increase lifespan.
Using a mouse model of longevity, Terry Combs and colleagues report that changes in metabolism can indeed increase longevity. They demonstrated that long-lived Snell dwarf mice burn less glucose and more fatty acids during periods of fasting, and as a result produce fewer free radicals.
The key to this switch may be adiponectin, a hormone produced by fat cells that helps lower glucose production and stimulates cells to use fat for energy instead. The researchers found that Snell mice had three times as much adiponectin in their blood as control mice; Snell mice also had fewer triglycerides in their cells, indicative of higher fat metabolism.
The benefit of burning fats instead of glucose for energy is that it produces fewer oxygen radicals which can damage cells and exacerbate the effects of aging. Confirming this, Combs and colleagues found far less free radical damage, measured as the frequency of a chemical modification on protein known as carbonyl groups, in Snell mice than controls.
Article: "Low utilization of circulating glucose after food withdrawal in Snell dwarf mice" by Natasha L. Brooks, Chad M. Trent, Carl F. Raetzsch, Kevin Flurkey, Gunnar Boysen, Michael T. Perfetti, Yo-Chan Jeong, Simon Klebanov, Kajal B. Patel, Valerie R. Khodush, Lawrence L. Kupper, David Carling, James A. Swenberg, David E. Harrison, and Terry P. Combs