Catabolic changes in cancer disease-, aging process- , critically ill patients, as well during chronic infection and inflammation are associated with weight loss, negative nitrogen balance and severe muscle wasting that can not be explained solely by reduced caloric intake. These conditions are associated with alterations in the acute phase mediator cytokines and insuline-like growth factor (IGF) system. This book provides an excellent review of acute phase mediators and IGF system components and a detailed description of an in vitro and in vivo experimental model system in a well-structured and uniquely didacted way. This is the first and only publication as such in the topic and fills an important gap. The present work should give to researchers a clear and concise general view of the subject, and a bunch of ideas for new projects, to specialists in medicine, veterinary medicine and biology sufficient information to understand the "secret" of cytokine- and IGF systems and its importance in anabolic- and catabolic mechanisms and to students a useful model and a fast and "painless" information how to give answers to scientific questions, and to create their thesis.