Fatty acid recycling in adipocytes: a role for glyceroneogenesis and phosphoenolpyruvate carboxykinase

• Published in: Biochemical Society transactions Vol. 31; no. Pt 6; p. 1125
• Main Authors: Forest, C, Tordjman, J, Glorian, M, Duplus, E, Chauvet, G, Quette, J, Beale, E G, Antoine, B
• Format: Journal Article
• Language: English
• Published: England 01-12-2003
• Subjects: Adipocytes - enzymology; Adipocytes - metabolism; Animals; Fatty Acids - metabolism; Glycerol - metabolism; Phosphoenolpyruvate Carboxykinase (ATP) - metabolism
• ISSN: 0300-5127
• DOI: 10.1042/bst0311125

FA (fatty acid) recycling in adipose tissue appears to be an important pathway for regulating FA release into the blood during fasting. Re-esterification requires G3P (glycerol 3-phosphate), which cannot be synthesized from glucose because glycolysis is much reduced under such circumstances. In addition, G3P can scarcely originate from glycerol since glycerol kinase has a very low activity in white adipose tissue. It was shown about 35 years ago that a metabolic pathway named glyceroneogenesis, which allows G3P synthesis from non-carbohydrate precursors like pyruvate, lactate or amino acids, is activated during fasting. The major enzyme in this pathway was shown to be PEPCK-C [cytosolic phosphoenolpyruvate carboxykinase (GTP); EC 4.1.1.32]. The present review analyses the mechanisms by which a series of hormones and nutrients affect PEPCK-C gene transcription and glyceroneogenesis and describes evidence for dysregulation of this pathway in type 2 diabetes.