Interaction of glucagon-like peptide-I (GLP-I) and galanin in insulin (beta TC-1)- and somatostatin (RIN T3)-secreting cells and evidence that both peptides have no receptors on glucagon (INR1G9)-secreting cells.
The interaction of glucagon-like peptide-I (GLP-I) and galanin in clonal endocrine pancreatic cells was characterized. By Northern blot analysis the presence of GLP-I receptor mRNA was shown in B (beta TC-1 cells) and D (RIN 1048-38) cells but not in A (INR1 G9) cells, thus confirming functional data demonstrating the absence of active GLP-I receptors on glucagon-producing cells. Galanin receptors were detected on B and D cells but not on A cells. In B and D cells galanin inhibited the GLP-I stimulated adenylate cyclase activity. Treatment of insulin- and somatostatin-producing cells with GLP-I increased intracellular cAMP levels, and this was dampened by galanin, GLP-I stimulated the activity of protein kinase A in B and D cells, which was also inhibited by galanin. Galanin alone did not influence B- and D-cell function. These data show that in the endocrine pancreas B and D cells but not A cells express GLP-I and galanin receptors. The interaction of GLP-I and galanin might act in the endocrine pancreas as a physiological inhibitor of the potent incretin hormone GLP-I. Therefore, we suggest galanin is a 'decretin'.
Fehmann
H C
HC
Department of Medicine, Philipps-University, Marburg, Germany.
Janssen
M
M
Göke
B
B
D000818:Animals; D002460:Cell Line; D004347:Drug Interactions; D019004:Galanin / Q000494:pharmacology* / Q000502:physiology; D005934:Glucagon / Q000378:metabolism* / Q000494:pharmacology* / Q000502:physiology; D052216:Glucagon-Like Peptide 1; D000067757:Glucagon-Like Peptide-1 Receptor; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology* / Q000502:physiology; D011498:Protein Precursors / Q000494:pharmacology* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D044088:Receptors, Galanin; D011964:Receptors, Gastrointestinal Hormone / Q000032:analysis*; D018027:Receptors, Glucagon / Q000032:analysis*; D013004:Somatostatin / Q000378:metabolism*
C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D007328:Insulin; D010446:Peptide Fragments; D011498:Protein Precursors; D012333:RNA, Messenger; D044088:Receptors, Galanin; D011964:Receptors, Gastrointestinal Hormone; D018027:Receptors, Glucagon; D013004:Somatostatin; D019004:Galanin; D052216:Glucagon-Like Peptide 1; D005934:Glucagon