Hypothalamic regulation of muscle metabolism

Purpose of review: The interest in obesity research has produced a large body of data describing the impact of neuronal signaling in the hypothalamus and brainstem on metabolic regulation in the periphery. Studies have historically focused on central regulation of metabolism in adipose and hepatic tissue. Recent studies highlight an important role for these same central regulatory centers in the control of muscle metabolism. This review will focus on these new studies, and will highlight the implications of these new data for the study of muscle catabolism in disease states. Recent findings: The balance of anabolism and catabolism in muscle requires activation of the hypothalamic-pituitary- adrenal axis as well as changes in energy-dependent signaling pathways in the muscle. It is now apparent that the sympathetic nervous system conveys much of this information between key metabolism-regulating nuclei in the hypothalamus and skeletal muscle. Summary: Peripheral signals conveying information regarding the metabolic status of the animal appear to alter the function of metabolic centers in the brain that in turn regulate energy partitioning in muscle via a sympathetic relay. Our understanding of how this system is regulated in normal physiological states and in obesity is providing important clues for understanding muscle catabolism in disease.