α-KETOGLUTARATE UPTAKE IN HUMAN FIBROBLASTS

✍ Scribed by C. AUSSEL; C. COUDRAY-LUCAS; E. LASNIER; L. CYNOBER; O.G. EKINDJIAN

• Book ID: 102565679
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 130 KB
• Volume: 20
• Category: Article
• ISSN: 1065-6995
• DOI: 10.1006/cbir.1996.0042

✦ Synopsis

Abstract

Glutamine requirements are increased during injury, in particular to sustain the needs of rapidly growing cells. This includes fibroblasts involved in wound healing. α‐Ketoglutarate (α‐KG) has been proved to be a potent precursor of glutamine. However, little is known about the process of its cell uptake. Since this first step could be crucial in α‐KG metabolism, we have characterized α‐ketoglutarate uptake in fibroblasts. Total uptake of α‐ketoglutarate was linear up to 1mmol and temperature independent. Rate of uptake was independent of the presence of Na^+^in the medium. Competition studies with another ketoacid demonstrated the non‐specificity of α‐ketoglutarate uptake. In addition, 4‐hydroxy‐α‐cyanocinnamate, a known inhibitor of anion transport, was ineffective on α‐ketoglutarate uptake. Taken as a whole, these data provide evidence that α‐ketoglutarate uptake in fibroblast occurs by an unmediated diffusion process. This suggests that α‐ketoglutarate uptake is not the controlling step in fibroblasts, i.e. only the availability of extracellular α‐ketoglutarate. This could be an advantage since during injury, cell membrane depolarization and dissipation of Na^+^gradient may limit cellular glutamine uptake.