Effects of glucagon-like peptide-1 (GLP-1) in RINm5F insulinoma cells. Stimulation of insulin secretion, insulin content, and insulin receptor binding.
Glucagon-like peptide-1 (GLP-1) is the major incretin hormone from the distal small intestine which stimulates basal and glucose-induced insulin secretion. Using the rat insulinoma cell line RINm5F (Gazdar et al. 1980) we investigated the effects of GLP-1 on insulin secretion, insulin content, and insulin receptor binding. During a 1 hour incubation, GLP-1 [1 nM] stimulated insulin secretion 2-fold (p < 0.01 vs controls). Incubating RINm5F for 24 h with GLP-1 [1 nM], a 1.6-fold higher cellular insulin content was observed (p < 0.01 vs controls). Moreover, GLP-1 induced a 2-fold higher capacity and a 15-fold higher affinity of 125I-insulin binding on the cell surface (p < 0.01 vs controls). Glucagon, known as a potent stimulator of insulin secretion, yielded a similar effect only in 1,000-fold higher concentrations, whereas the intracellular insulin content as well as insulin receptor binding was not increased. Taken together, in RINm5F insulinoma cells GLP-1 potently stimulates insulin secretion and insulin content, and improves insulin receptor binding.
Jehle
P M
PM
Department of Internal Medicine I, University of Ulm, Germany.
Jehle
D
D
Fussgänger
R D
RD
Adler
G
G
D000818:Animals; D005934:Glucagon / Q000494:pharmacology*; D052216:Glucagon-Like Peptide 1; D007328:Insulin / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008854:Microscopy, Electron; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology*; D011498:Protein Precursors / Q000494:pharmacology*; D051381:Rats; D011972:Receptor, Insulin / Q000187:drug effects / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D007328:Insulin; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D011498:Protein Precursors; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D011972:Receptor, Insulin