title: Extrahypothalamic expression of the glucagon-like peptide-2 receptor is coupled to reduction of glutamate-induced cell death in cultured hippocampal cells.
abstract: Proglucagon-derived glucagon-like peptide-2 (GLP-2) is liberated in enteroendocrine cells and neurons. GLP-2 regulates energy absorption and epithelial integrity in the gastrointestinal tract, whereas GLP-2 action in the central nervous system remains poorly defined. We identified proglucagon and GLP-2 receptor (GLP-2R) mRNA transcripts by RT-PCR in multiple regions of the developing and adult rat central nervous system. GLP-2R mRNA transcripts were localized by in situ hybridization to the hippocampus, hypothalamus, nucleus of the solitary tract, parabrachial nucleus, supramammillary nucleus, and substantia nigra. The bioactive form of GLP-2, GLP-2-(1-33) was detected by RIA and HPLC analysis in the fetal and adult brainstem and hypothalamus. GLP-2 stimulated increases in cAMP accumulation in postnatal d 8, but not embryonic d 14, dispersed neonatal rat brainstem tissues. The actions of GLP-2 were independent of the GLP-1R antagonist exendin-(9-39), and GLP-2 stimulated cAMP accumulation in hippocampal cell cultures from both wild-type and GLP-1R(-/-) mice. GLP-2 significantly reduced glutamate-induced excitotoxic injury in hippocampal cells via a protein kinase A-dependent pathway, but had no effect on the rate of cell proliferation. These findings establish the presence of a functional GLP-2-GLP-2R axis in the developing rodent brain and demonstrate that GLP-2 exerts cytoprotective actions in cells derived from the central nervous system.
authors.affiliation: Department of Medicine, University of Toronto, Toronto General Hospital, Banting and Best Diabetes Center, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Lovshin
authors.forename: Q
authors.initials: Q
authors.lastname: Huang
authors.forename: R
authors.initials: R
authors.lastname: Seaberg
authors.forename: P L
authors.initials: PL
authors.lastname: Brubaker
authors.forename: D J
authors.initials: DJ
authors.lastname: Drucker
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005260:Female; D005333:Fetus; D018507:Gene Expression Regulation, Developmental; D053767:Glucagon-Like Peptide 2; D000067757:Glucagon-Like Peptide-1 Receptor; D004763:Glucagon-Like Peptides; D018698:Glutamic Acid / Q000633:toxicity; D006624:Hippocampus / Q000166:cytology* / Q000196:embryology; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D018027:Receptors, Glucagon / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: C000593834:Glp1r protein, mouse; C000593835:Glp1r protein, rat; D053767:Glucagon-Like Peptide 2; D000067757:Glucagon-Like Peptide-1 Receptor; D010455:Peptides; D018027:Receptors, Glucagon; D018698:Glutamic Acid; D004763:Glucagon-Like Peptides; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases