title: Insulinostatic activity of cerebellin--evidence from in vivo and in vitro studies in rats.
abstract: Cerebellin (CER) is a neuromodulatory hexadecapeptide that originates from the precursor protein precerebellin (Cbln1). Four highly homologous isoforms of Cbln are known (Cbln1-Cbln4), which are expressed in the central nervous system (CNS) and in peripheral tissues. CER modulates synaptic structure formation in the CNS, whereas in the peripheral tissues CER regulates catecholamine secretion. Cbln is also expressed in the pancreas; however, its function in the pancreas is unknown. Here, we demonstrate the role of CER in regulating insulin secretion in vivo and in vitro. We identified Cbln1 and Cbln3 transcripts in rat pancreatic islets and detected Cbln-immunoreactivity, predominantly located in the periphery of the rat endocrine pancreas. In vivo, CER reduced plasma insulin levels in rats after 1 and 2 h. CER decreased insulin secretion from isolated rat pancreatic islets at high (11 mM), but not at low (3.33 mM) glucose concentration. CER inhibited stimulated insulin secretion from clonal rat insulinoma (INS-1) cells, reduced forskolin-induced production of cAMP and intracellular calcium concentration. Our study demonstrates for the first time that Cbln1 and Cbln3 are expressed in the rat endocrine pancreas. Furthermore, we identify CER as an insulinostatic factor, which decreases intracellular cAMP production and calcium in INS-1 cells.
authors.affiliation: Medizinische Klinik mit Schwerpunkt Hepatologie, Gastroenterologie & Interdisziplinäres Stoffwechsel-Centrum: Endokrinologie, Diabetes und Stoffwechsel Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Mathias Z
authors.initials: MZ
authors.lastname: Strowski
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Kaczmarek
authors.forename: Stefan
authors.initials: S
authors.lastname: Mergler
authors.forename: Bertram
authors.initials: B
authors.lastname: Wiedenmann
authors.forename: Danuta
authors.initials: D
authors.lastname: Domin
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Szwajkowski
authors.forename: Tatiana
authors.initials: T
authors.lastname: Wojciechowicz
authors.forename: Marek
authors.initials: M
authors.lastname: Skrzypski
authors.forename: Dawid
authors.initials: D
authors.lastname: Szczepankiewicz
authors.forename: Tomasz
authors.initials: T
authors.lastname: Szkudelski
authors.forename: Marcin
authors.initials: M
authors.lastname: Rucinski
authors.forename: Ludwik K
authors.initials: LK
authors.lastname: Malendowicz
authors.forename: Krzysztof W
authors.initials: KW
authors.lastname: Nowak
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002460:Cell Line; D000242:Cyclic AMP / Q000032:analysis; D005260:Female; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D046790:Pancreas, Exocrine / Q000187:drug effects / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D007328:Insulin; D009419:Nerve Tissue Proteins; D011498:Protein Precursors; C046788:cerebellin; D000242:Cyclic AMP; D002118:Calcium