Anabolic and Catabolic Signaling Pathways That Regulate Skeletal Muscle Mass

Skeletal muscle mass is primarily dictated by the balance between the rates of protein synthesis and degradation. Over the last decade, significant progress has been made in defining the anabolic and catabolic signaling pathways that control skeletal muscle mass through the regulation of protein synthesis and degradation. The purpose of this review is to briefly describe known and emerging signaling pathways involved in the regulation of skeletal muscle mass. Two important themes have come to light: (1) the degree of cross talk between and among anabolic and catabolic signaling pathways involved in the control of skeletal muscle hypertrophy and atrophy and (2) the balance between anabolism and catabolism that is required to facilitate a proper hypertrophic response. A more in-depth understanding of the anabolic and catabolic signaling pathways that regulate skeletal muscle mass will provide a critical foundation for the development of more effective training programs and nutritional aids to enhance athletic performance.