Electrogenic arginine transport mediates stimulus-secretion coupling in mouse pancreatic beta-cells.
1. We have investigated the mechanism by which L-arginine stimulates membrane depolarization, an increase of intracellular calcium ([Ca2+]i) and insulin secretion in pancreatic beta-cells. 2. L-Arginine failed to affect beta-cell metabolism, as monitored by NAD(P)H autofluorescence. 3. L-Arginine produced a dose-dependent increase in [Ca2+]i, which was dependent on membrane depolarization and extracellular calcium. 4. The cationic amino acids L-ornithine, L-lysine, L-homoarginine (which is not metabolized) and NG-monomethyl-L-arginine (L-NMMA, a nitric oxide synthase inhibitor) produced [Ca2+]i responses similar to that produced by L-arginine. The neutral nitric oxide synthase inhibitors NG-nitro-L-arginine (L-NNA) and N omega-monomethyl-L-arginine (L-NAME) also increased [Ca2+]i. D-Arginine was ineffective. 5. L-Arginine did not affect whole-cell Ca2+ currents or ATP-sensitive K+ currents, but produced an inward current that was carried by the amino acid. 6. The reverse transcriptase-polymerase chain reaction demonstrated the presence of messenger RNA for the murine cationic amino acid transporters mCAT2A and mCAT2B within the beta-cell. 7. L-Arginine did not affect beta-cell exocytosis as assayed by changes in cell capacitance. 8. Our data suggest that L-arginine elevates [Ca2+]i and stimulates insulin secretion as a consequence of its electrogenic transport into the beta-cell. This uptake is mediated by the mCAT2A transporter.
Smith
P A
PA
University Laboratory of Physiology, Oxford, UK.
Sakura
H
H
Coles
B
B
Gummerson
N
N
Proks
P
P
Ashcroft
F M
FM
D017398:Alternative Splicing; D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism*; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004553:Electric Conductivity; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis; D005456:Fluorescent Dyes / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D007700:Kinetics; D008562:Membrane Glycoproteins; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011991:Receptors, Virus; D014966:Xanthenes / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D000814:Aniline Compounds; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D007328:Insulin; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D011991:Receptors, Virus; D014966:Xanthenes; C070506:ecotropic murine leukemia virus receptor; D019335:Nitroarginine; C059715:Fluo-3; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester