An extremely low frequency magnetic field attenuates insulin secretion from the insulinoma cell line, RIN-m.
In this study, we investigated the effects of exposure to an extremely low frequency magnetic field (ELFMF) on hormone secretion from an islet derived insulinoma cell line, RIN-m. We stimulated RIN-m cells to secrete insulin under exposure to an ELFMF, using our established system for the exposure of cultured cells to an ELFMF at 5 mT and 60 Hz, or under sham exposure conditions for 1 h and observed the effects. In the presence of a depolarizing concentration of potassium (45 mM KCl), exposure to ELFMF significantly attenuated insulin release from RIN-m cells, compared to sham exposed cells. Treatment with nifedipine reduced the difference in insulin secretion between cells exposed to an ELFMF and sham exposed cells. The expression of mRNA encoding synaptosomal associated protein of 25 kDa (SNAP-25) and synaptotagmin 1, which play a role in exocytosis in hormone secretion and influx of calcium ions, decreased with exposure to an ELFMF in the presence of 45 mM KCl. These results suggest that exposure to ELFMF attenuates insulin secretion from RIN-m cells by affecting calcium influx through calcium channels.
Sakurai
Tomonori
T
Department of Organ Reconstruction, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.
Satake
Akira
A
Sumi
Shoichiro
S
Inoue
Kazutomo
K
Miyakoshi
Junji
J
D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins; D045744:Cell Line, Tumor; D017931:DNA Primers; D007328:Insulin / Q000235:genetics / Q000378:metabolism*; D000078790:Insulin Secretion; D007340:Insulinoma / Q000378:metabolism*; D008280:Magnetics; D008562:Membrane Glycoproteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D050825:Synaptosomal-Associated Protein 25; D050863:Synaptotagmin I; D050857:Synaptotagmins
D002135:Calcium-Binding Proteins; D017931:DNA Primers; D007328:Insulin; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D050863:Synaptotagmin I; C494312:Syt1 protein, rat; D050857:Synaptotagmins