Defects in Adaptive Energy Metabolism with CNS-Linked Hyperactivity in PGC-1α Null Mice

Abstract PGC-1α is a coactivator of nuclear receptors and other transcription factors that regulates several metabolic processes, including mitochondrial biogenesis and respiration, hepatic gluconeogenesis, and muscle fiber-type switching. We show here that, while hepatocytes lacking PGC-1α are defective in the program of hormone-stimulated gluconeogenesis, the mice have constitutively activated gluconeogenic gene expression that is completely insensitive to normal feeding controls. C/EBPβ is elevated in the livers of these mice and activates the gluconeogenic genes in a PGC-1α-independent manner. Despite having reduced mitochondrial function, PGC-1α null mice are paradoxically lean and resistant to diet-induced obesity. This is largely due to a profound hyperactivity displayed by the null animals and is associated with lesions in the striatal region of the brain that controls movement. These data illustrate a central role for PGC-1α in the control of energy metabolism but also reveal novel systemic compensatory mechanisms and pathogenic effects of impaired energy homeostasis.