Fatty acid recycling in adipocytes: a role for glyceroneogenesis and phosphoenolpyruvate carboxykinase.
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.
Forest
C
C
UMR-S 530 Inserm-Université René Descartes, Centre Universitaire-U.F.R. Biomédicale, 45 rue des Saints-Pères, 75006 Paris, France. claude.forest@biomedicale.univ-paris5.fr
Tordjman
J
J
Glorian
M
M
Duplus
E
E
Chauvet
G
G
Quette
J
J
Beale
E G
EG
Antoine
B
B
D017667:Adipocytes / Q000201:enzymology / Q000378:metabolism*; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000378:metabolism*
D005227:Fatty Acids; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D005990:Glycerol