title: Defect of insulin signal in peripheral tissues: Important role of ceramide.
abstract: In healthy people, balance between glucose production and its utilization is precisely controlled. When circulating glucose reaches a critical threshold level, pancreatic β cells secrete insulin that has two major actions: to lower circulating glucose levels by facilitating its uptake mainly into skeletal muscle while inhibiting its production by the liver. Interestingly, dietary triglycerides are the main source of fatty acids to fulfill energy needs of oxidative tissues. Normally, the unconsumed fraction of excess of fatty acids is stored in lipid droplets that are localized in adipocytes to provide energy during fasting periods. Thus, adipose tissue acts as a trap for fatty acid excess liberated from plasma triglycerides. When the buffering action of adipose tissue to store fatty acids is impaired, fatty acids that build up in other tissues are metabolized as sphingolipid derivatives such as ceramides. Several studies suggest that ceramides are among the most active lipid second messengers to inhibit the insulin signaling pathway and this review describes the major role played by ceramide accumulation in the development of insulin resistance of peripherals tissues through the targeting of specific proteins of the insulin signaling pathway.
authors.affiliation: Rima Hage Hassan, Olivier Bourron, Eric Hajduch, INSERM, UMR-S 1138, Centre de Recherche des Cordeliers, F-75006 Paris, France.
authors.forename: Rima
authors.initials: R
authors.lastname: Hage Hassan
authors.affiliation: Rima Hage Hassan, Olivier Bourron, Eric Hajduch, INSERM, UMR-S 1138, Centre de Recherche des Cordeliers, F-75006 Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Bourron
authors.affiliation: Rima Hage Hassan, Olivier Bourron, Eric Hajduch, INSERM, UMR-S 1138, Centre de Recherche des Cordeliers, F-75006 Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Hajduch
keywords: Akt; Ceramide synthase; Diabetes; Insulin resistance; Insulin signaling; Lipids; Palmitate; Protein kinase C ζ/λ; Protein phosphatase 2A; Sphingolipid; Triglycerides