The research, scheduled to be published Jan. 14 in Nature Metabolism, reveals a potential target for treating metabolic disorders.
Our bodies use several systems to maintain precise control of energy homeostasis -- balancing the amount of energy we use and the calories we consume. The hormone leptin, for example, signals the brain to suppress appetite and increase burning of calories when energy stores are high.
Side - Equation - Energy - Expenditure - Jiandie
"But much less is known about the other side of this equation: energy expenditure," said Jiandie Lin, professor at the LSI and senior study author. "How does the body sense rapid depletion of energy, and how does it tell the brain to adjust the body's metabolism and maintain homeostasis? That's the question we set out to answer."
By parsing gene expression data in mouse tissues, Lin and his colleagues found a hormone that was elevated when mice were burning a lot of energy, such as when they needed to maintain body temperature in a cold environment. This hormone, tsukushi (or TSK), is excreted primarily by the liver -- a central player in nutritional, metabolic and hormonal pathways.
TSK - Energy - Expenditure - Lin - Professor
"We think that TSK is somehow dampening energy expenditure," said Lin, who is also a professor of cell and developmental biology at the U-M Medical School. "When there is a rapid loss of energy, it puts a brake on metabolism. If we remove this brake, our prediction was that the mice would have accelerated burning of calories. And that turned out to be the case."
When mice temporarily went without food, those lacking TSK lost significantly...
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