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Hormone Duo Promotes Loss of Fat Reserves

Due to the coordinated action of the two hormones glucagon and fibroblast growth factor 21 (FGF21), there is a decreased food ­intake and increased fat burning. Therefore, the two substances are ­considered to be potential targets for the treatment of metabolic diseases such as obesity and type 2 diabetes.

The interaction of the two hormones glucagon and fibroblast growth factor 21 (FGF21) has a decisive impact on lipid metabolism and body weight. Their coordinated action leads to decreased food intake and increased fat burning, as scientists of the Institute for Diabetes and Obesity in cooperation with the Metabolic Diseases Institute of the University of Cincinnati, USA, discovered. The two neurotransmitters are thus considered to be promising target structures for treating obesity and type 2 diabetes.

As “hunger hormone”, glucagon mediates a reduction of the energy reserves of the body. For the first time, the scientists found that the direct interaction with the neurotransmitter FGF21 is required for this effect. The team led by Kerstin Stemmer and Matthias Tschöp studied the long-term effect of glucagon in a mouse model and showed that this effect is characterized by decreased food intake, increased fat burning and decreasing cholesterol levels. At the same time there was a significant increase in the hormone FGF21. This effect could be detected not only in mice but also in humans. If the mice lacked FGF21 due to a genetic defect (FGF21 knock-out mice), glucagon lost its positive properties on metabolism. From this the scientists infer that FGF21 is essential for the effects mediated by glucagon on fat burning and cholesterol levels.

The results support earlier work by the team according to which fusion hormones from glucagon and glucagon-like peptides (e.g. glucagon-like-peptide 1, GLP-1) have a significant potential for the treatment of obesity and diabetes. Until now, however, the signaling pathway was unknown through which glucagon reduces fat reserves. In further studies the details of the hormonal interaction of glucagon and FGF21 shall be explored to examine potential applications for the treatment of metabolic diseases.

The main task of the peptide hormone glucagon, which is formed in the alpha islet cells of the pancreas, is to increase the blood glucose level. When blood glucose levels drop, glucagon is released into the blood stream and is the counter-regulatory hormone opposing insulin action in glucose and lipid metabolism.