A regulatory protein RS1 fragment or a nucleic acid molecule encoding the regulatory protein RS1 fragment for the preparation of a pharmaceutical composition, food and/or food supplements for the amelioration, prevention and/or treatment of a metabolic disease or a secondary disorder caused by a (pathological) modification of homeostasis, wherein the RS1 fragment is characterized in comprising at least the amino acid sequence Q-C-P Glutamine-Cysteine-Proline) or derivatives thereof, is provided. Also provided is a method for the amelioration, prevention and/or treatment of a metabolic disease or a secondary disorder caused by a (pathological) modification of homeostasis comprising administering a pharmaceutically active amount of a regulatory protein RS1 fragment or a nucleic acid molecule encoding a regulatory protein RS1 fragment, wherein the RS1 fragment comprises at least the amino acid sequence Q-C-P or derivatives thereof.
