title: Differential expression of the glutamate transporter GLT-1 in pancreas.
abstract: The glutamate uptake transporter GLT-1 is best understood for its critical role in preventing brain seizures. Increasing evidence argues that GLT-1 also modulates, and is modulated by, metabolic processes that influence glucose homeostasis. To investigate further the potential role of GLT-1 in these regards, the authors examined GLT-1 expression in pancreas and found that mature multimeric GLT-1 protein is stably expressed in the pancreas of wild-type, but not GLT-1 knockout, mice. There are three primary functional carboxyl-terminus GLT-1 splice variants, called GLT-1a, b, and c. Brain and liver express all three variants; however, the pancreas expresses GLT-1a and GLT-1b but not GLT-1c. Quantitative real time-PCR further revealed that while GLT-1a is the predominant GLT-1 splice variant in brain and liver, GLT-1b is the most abundant splice variant expressed in pancreas. Confocal microscopy and immunohistochemistry showed that GLT-1a and GLT-1b are expressed in both islet β- and α-cells. GLT-1b was also expressed in exocrine ductal domains. Finally, glutamine synthetase was coexpressed with GLT-1 in islets, which suggests that, as with liver and brain, one possible role of GLT-1 in the pancreas is to support glutamine synthesis.
authors: Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA.
authors: James S
authors: JS
authors: Meabon
authors: Aven
authors: A
authors: Lee
authors: Kole D
authors: KD
authors: Meeker
authors: Lynn M
authors: LM
authors: Bekris
authors: Robert K
authors: RK
authors: Fujimura
authors: Chang-En
authors: CE
authors: Yu
authors: G Stennis
authors: GS
authors: Watson
authors: David V
authors: DV
authors: Pow
authors: Ian R
authors: IR
authors: Sweet
authors: David G
authors: DG
authors: Cook
mesh_terms: D000818:Animals; D027342:Excitatory Amino Acid Transporter 2 / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D027342:Excitatory Amino Acid Transporter 2; C493396:Slc1a2 protein, mouse