title: Effects of galanin on proinsulin mRNA and insulin biosynthesis in normal islets.
abstract: Whether the potent insulinostatic neuropeptide galanin also inhibits insulin production in normal islets is not known. Therefore, isolated mouse islets were incubated for 90 min in 2.8 or 16.7 mmol/l glucose and 3H-labelled leucine with addition of mouse galanin at 1, 10 or 100 nmol/l. Galanin potently inhibited glucose-stimulated insulin secretion at both 10 and 100 nmol/l (P < 0.05), and proinsulin biosynthesis was slightly inhibited at 100 nmol/l (P < 0.05). Also, mouse islets were incubated for 48 h at 5 or 16.7 mmol/l glucose with galanin at 1, 10 or 100 nmol/l and proinsulin mRNA was determined by hybridisation of extracted RNA with digoxigenin-labelled oligonucleotide insulin probe. Proinsulin mRNA levels were approximately doubled by glucose at 16.7 mmol/l compared at 5 mmol/l (P < 0.05). Galanin did not affect islet proinsulin mRNA levels. Therefore, galanin seems to mainly regulate insulin secretion without any important role in the regulation of insulin availability in normal islets.
authors.affiliation: Department of Medicine, Lund University, Malmö University Hospital, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Lindskog
authors.forename: S
authors.initials: S
authors.lastname: Gregersen
authors.forename: K
authors.initials: K
authors.lastname: Hermansen
authors.forename: B
authors.initials: B
authors.lastname: Ahrén
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D019004:Galanin / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000096:biosynthesis* / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D011384:Proinsulin / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000378:metabolism; D014316:Tritium
chemical_list: D007328:Insulin; D012333:RNA, Messenger; D014316:Tritium; D019004:Galanin; D011384:Proinsulin; D007930:Leucine; D005947:Glucose