title: Influence of melatonin receptor signalling on parameters involved in blood glucose regulation.
abstract: The pineal hormone melatonin is known to influence insulin secretion via the G-protein-coupled receptor isoforms MT1 and MT2. The present study was aimed to further elucide the impact of melatonin on blood glucose regulation. To this end, mouse lines were used, in which one of the two or both melatonin receptors were deleted. In comparison with wild-type mice of the same age (8-12 months old), increased plasma insulin and melatonin levels and decreased blood glucose levels and body weights were detected in the MT1- and double-knockout lines. The elimination of melatonin receptor signalling also altered blood glucose concentrations, body weight and melatonin and insulin levels when comparing wild-type and receptor knockout mice of different ages (6 wk and 8-12 months old); such changes, however, were dependent on the type of receptor deleted. Furthermore, reverse transcription polymerase chain reaction results provided evidence that melatonin receptor deficiency has an impact on transcript levels of pancreatic islet hormones as well as on pancreatic and hepatic glucose transporters (Glut1 and 2). Under stimulated insulin secretion in the presence of melatonin in the rat insulinoma β-cells INS-1, the Glut1 transcript level was decreased. In conclusion, the present findings demonstrate that melatonin receptor knockout types affect blood glucose levels, body weight, plasma levels of melatonin and insulin, as well as pancreatic hormone and Glut1 expression in significantly different manners.
authors.affiliation: Institute of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle, Germany.
authors.forename: Ivonne
authors.initials: I
authors.lastname: Bazwinsky-Wutschke
authors.forename: Lars
authors.initials: L
authors.lastname: Bieseke
authors.forename: Eckhard
authors.initials: E
authors.lastname: Mühlbauer
authors.forename: Elmar
authors.initials: E
authors.lastname: Peschke
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000235:genetics / Q000378:metabolism*; D001835:Body Weight / Q000235:genetics; D045744:Cell Line, Tumor; D005260:Female; D005934:Glucagon / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051272:Glucose Transporter Type 1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D007328:Insulin / Q000097:blood; D008297:Male; D008550:Melatonin / Q000097:blood; D051379:Mice; D018345:Mice, Knockout; D009928:Organ Specificity; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D044122:Receptor, Melatonin, MT1 / Q000235:genetics / Q000378:metabolism*; D044123:Receptor, Melatonin, MT2 / Q000235:genetics / Q000378:metabolism*; D013004:Somatostatin / Q000032:analysis / Q000235:genetics / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D051272:Glucose Transporter Type 1; D007328:Insulin; D012333:RNA, Messenger; D044122:Receptor, Melatonin, MT1; D044123:Receptor, Melatonin, MT2; C495678:Slc2a1 protein, mouse; D013004:Somatostatin; D005934:Glucagon; D008550:Melatonin
keywords: INS-1; glucose transporter; melatonin receptor knockout mouse; pancreatic islet hormones