New York, Nov 19 (IANS): Discovery of a previously unknown hormone that serves as a messenger from fat cells to the liver could pave way for new treatment for metabolic disorders, finds research.

The hormone, NRG4, is secreted by so-called brown fat cells and communicates with the liver to regulate the conversion of sugar into fat, the researchers discovered in a mice study.

Mice without NRG4 became obese and developed hallmarks of type 2 diabetes and fatty liver disease.

When scientists genetically elevated NRG4 levels in these mice, however, the animals were protected from these metabolic disorders when fed a high-calorie, high-fat diet.

"In all models of obesity, NRG4 expression is reduced," said Jiandie Lin from University of Michigan in the US.

And in humans, the amount of NRG correlates negatively with obesity.

"We think obesity is a state of NRG4 deficiency," Lin said.

Once bound to its receptor on liver cells, NRG4 reduces the conversion of sugar into fat, a process thought to promote disorders associated with obesity, particularly fatty liver.

Without NRG4, the liver is abnormally active in converting sugar into fat, leading to metabolic disorders, the findings showed.

The research was published in the journal Nature Medicine.