Postnatal Development of IGF-I and IGF-II Genes in Goat Skeletal Muscle and Liver Tissues

Insulin like Growth Factors (IGF-I and IGF-II) play an important role in regulation of skeletal muscle growth and act as mediator of growth hormone during muscle development and differentiation. In this study, the expression profiling of goat IGF-I and IGF-II genes was investigated in liver and skeletal muscle at six postnatal development stages (3, 15, 30, 60, 90 and 120 days) and two types of muscles (longissimus dorsi muscle, LD; triceps brachii muscle, TB) using relative real-time quantitative PCR. The results showed that IGF-I gene was expressed at the highest level in the liver with relatively high expression levels in spleen, skeletal muscle and heart. IGF-II gene was predominantly expressed in spleen, followed by liver and longissimus dorsi muscle, whereas expression in heart was relatively weak. IGF-I and IGF-II genes had different expression profiles during the postnatal period of the goat liver and skeletal muscle development. Moreover, IGF-I was expressed at higher levels in triceps brachii muscles compared with longissimus dorsi muscles. The present study provided the comprehensive understanding of IGF-I and IGF-II expression during liver and muscle development and laid the basis for further studies on their roles in goat liver and skeletal muscle development.