Genetic Control of Carbon Utilization During Hibernation: Mechanistic Considerations
During hibernation, mammals rely heavily on lipid stores to provide the fuel necessary to survive the winter. Pyruvate dehydrogenase kinase isozyme 4 (PDK-4) plays a key role in gating carbohydrate catabolism and allowing the switch to lipid metabolism. Earlier we reported that PDK-4 was up-regulated in the heart of the thirteen-lined ground squirrel during hibernation (Andrews et al., 1998). A similar induction of PDK-4 was seen in rat skeletal muscle after administration of WY-14,643, a known peroxisome proliferator and ligand for peroxisome proliferator-activated receptor subtype alpha (PPARoc; Wu et al., 1999). In light of this evidence that PPARα may activate PDK-4 expression, we review the role that PPARs play in lipid metabolism and thermogenesis and discuss their potential as regulators of metabolism during hibernation.
KeywordsCarbohydrate Cysteine Pyruvate Prostaglandin Isopropanol
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