Chen Hou (Department of Biological Sciences, Missouri University of Science and Technology)
Abstract. Diet restriction (DR) and genetic interference (GI) with growth hormone function lead to smaller adult body mass and extended lifespan in mammals, suggesting tradeoffs between growth and longevity. Despite a rich body of empirical data, still largely missing is a theoretical framework that specifies and makes quantitative predictions on the tradeoffs. In this talk I will present a simple mechanistic model, which predicts that, in the same way, DR and GI channel extra metabolic energy to somatic maintenance by altering animal’s energy budget and suppressing growth, thereby extending lifespan. The model derives a quantitative relationship between lifespan extension and body mass reduction. Empirical data collected from a diverse set of studies on DR and GI strongly supports the prediction. The detailed energy tradeoffs revealed by the model offers an answer to the long-standing question raised by the free-radical theory of aging, why DR and GI animals live much longer without largely lowering their metabolic rates.