The effects of polymyxin B, a protein kinase C inhibitor, on insulin secretion from intact and permeabilized islets of Langerhans.
Polymyxin B (0.01-1 mM), a polyamine antibiotic, inhibited both phorbol ester- and glucose-stimulated insulin secretion from isolated rat islets of Langerhans. This inhibition was rapidly reversible. Assay of the cytosolic protein kinase C by measurement of incorporation of labelled phosphate into a histone substrate demonstrated the presence of activity in islet extracts which could be stimulated by 12-O-tetradecanoylphorbol-13-acetate and inhibited by polymyxin B. These results suggest that protein kinase C plays a role in glucose-induced insulin secretion.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008854:Microscopy, Electron; D011112:Polymyxin B / Q000494:pharmacology*; D011113:Polymyxins / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007328:Insulin; D011113:Polymyxins; D011493:Protein Kinase C; D005947:Glucose; D011112:Polymyxin B; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium