Functional dissection of the insulin-like growth factor (IGF) svstem – prospects for animal breeding

Abstract. Growth is a biological phenomenon that is subject to complex endo-, para-, and autocrine control mechanisms. In addition to insulin, thyroid hormones, sex steroids, and growth hormone (GH), components of the IGF system have been identified as key players in growth regulation. However, since altered growth is often associated with multiple changes in this complex regulatory network, the specific effects of individual components remain to be determined. Therefore, our lab focused on the functional dissection of the IGF system using transgenic mice and other animal models which are characterized by altered expression of individual members of this system. Here we review some of our findings identifying members of the IGF family as candidate genes which may affect important traits in livestock production.