In mammals, brown adipose tissue generates heat by burning fat reserves. The ability to sustain high body temperatures without muscular effort – non-shivering thermogenesis – played a key role during evolution both for reproduction as well as for survival in cooler climates.
In a study headed by Dr. Martin Jastroch and Dr. Carola Meyer of the Institute for Diabetes and Obesity (IDO) at Helmholtz Zentrum München and in collaboration with scientists of the Department of Animal Physiology of the Faculty of Biology of the University of Marburg and the Mitochondrial Biology Unit of the Medical Research Council, Cambridge, UK, the team of scientists showed that fully functional brown adipose tissue developed early in evolution. For this purpose they studied the lesser hedgehog tenrec (Echinops telfairi), which with respect to evolutionary development is a precursor of “higher” eutherian mammals. In contrast to higher mammals, the tenrec does not sustain a constant body temperature, but has brown adipose tissue and the active uncoupling protein UCP1, which is essential for fat burning.
From these findings the scientists concluded that fat burning is an early evolutionary physiological process that is independent of body temperature. “These conclusions from the study about the evolution and function of brown adipose tissue suggest a novel view of energy metabolism,” said Dr. Martin Jastroch, lead author of the publication.
Against this background, the scientists want to use the technological approaches developed in the study to identify additional activators of fat burning. They are focusing on uncoupling proteins like UCP1 that are crucially involved in the equilibrium of energy balance. Over the long term these results will help develop new therapeutic concepts of fat burning to combat excess fat reserves, for example in overweight and obesity.
Oelkrug, R. et al. (2013). Brown fat in a protoendothermic mammal fuels eutherian evolution, Nature Communications,doi: 10.1038/ncomms3140