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Reduction in voltage-gated K+ currents in primary cultured rat pancreatic beta-cells by linoleic acids


, : Reduction in voltage-gated K+ currents in primary cultured rat pancreatic beta-cells by linoleic acids. Endocrinology 147(2): 674-682

Free fatty acids (FFAs), in addition to glucose, have been shown to stimulate insulin release through the G protein-coupled receptor (GPCR)40 receptor in pancreatic beta-cells. Intracellular free calcium concentration ([Ca(2+)](i)) in beta-cells is elevated by FFAs, although the mechanism underlying the [Ca(2+)](i) increase is still unknown. In this study, we investigated the action of linoleic acid on voltage-gated K(+) currents. Nystatin-perforated recordings were performed on identified rat beta-cells. In the presence of nifedipine, tetrodotoxin, and tolbutamide, voltage-gated K(+) currents were observed. The transient current represents less than 5%, whereas the delayed rectifier current comprises more than 95%, of the total K(+) currents. A long-chain unsaturated FFA, linoleic acid (10 microm), reversibly decreased the amplitude of K(+) currents (to less than 10%). This reduction was abolished by the cAMP/protein kinase A system inhibitors H89 (1 microm) and Rp-cAMP (10 microm) but was not affected by protein kinase C inhibitor. In addition, forskolin and 8'-bromo-cAMP induced a similar reduction in the K(+) current as that evoked by linoleic acid. Insulin secretion and cAMP accumulation in beta-cells were also increased by linoleic acid. Methyl linoleate, which has a similar structure to linoleic acid but no binding affinity to GPR40, did not change K(+) currents. Treatment of cultured cells with GPR40-specific small interfering RNA significantly reduced the decrease in K(+) current induced by linoleic acid, whereas the cAMP-induced reduction of K(+) current was not affected. We conclude that linoleic acid reduces the voltage-gated K(+) current in rat beta-cells through GPR40 and the cAMP-protein kinase A system, leading to an increase in [Ca(2+)](i) and insulin secretion.

US$19.90

PMID: 16254037

DOI: 10.1210/en.2005-0225


Other references

Uchio T., 1983: Paleo-environment of the formation of the Kuroko deposits in the western Hokuroku District, Akita Prefecture, Northeast Japan. Journal of the Faculty of Engineering, University of Tokyo, Series B 37(2): 145-178

Lundberg, I.; Ulfgren, A.K.istin; Andersson, U.; Klareskog, L., 1995: An immunohistochemical analysis of cytokine pattern in inflammatory muscle disease. Arthritis & Rheumatism 38(9 SUPPL ): S167

Cherkesova, SV., 1969: Rhynchonellids of the family Trigonirhynchiidae Mclaren from the Tareyan supporting stratum (central Taimyr).. Uchenye Zapiski Nauchno-Issledovatel'skii Institut Geologii Arktiki Paleontologiya I Biostratigrafiya, 23-37 No. 26

Kanda, Y.; Hisayasu, S.; Fukai, F.; Takase, B., 2005: Milk growth factor (MGF) induces transformation into ATDC5 cells, prechondrocytes, and cooperates with retinoic acid to transform the cells into new forms. The effects of milk growth factor (MGF) showed the transformation of ATDC5 prechondrocytes and differed from that of retinoic acid (RA) as follows. MGF (200 ng/ml) did not suppress the proliferation of ATDC5 cells, though RA (1x10-7 M) suppressed...

Machard, P., 1976: French carabid fauna. 1. Entomologiste 32 (2) 60-65

Ayub M.; Yusuf M.; Beg M.A.; Faruqi F.A., 1988: Pozzolanic properties of burnt clays. Pakistan Journal of Scientific and Industrial Research 31(1): 1-6

Kabey, A.Kabey.A.; Lubanga, M.; Tshamba, M.; Kaut, M.; Kakambal, K.; Muteya, M.; Manzanza, K.; Kalal, K., 2016: Anesthesia practice in Lubumbashi: indications, types of surgery and patient types. Pan African Medical Journal 21: 240-240

Alabaraoye, E.; von Eschwege, K.G.; Loganathan, N., 2014: Synthesis and kinetics of sterically altered photochromic dithizonatomercury complexes. Following a previous study where 12 electronically altered dithizones were synthesized, here we report on attempts to synthesize 26 dithizones. The purpose was to explore the boundaries within which dithizones may be synthesized, explore spectral...

Klaus, S.; Oedekoven, A.; Oedekoven, B.; Mottagy, K.; Reul, H.; Glasmacher, B., 2001: In vitro blood damage by high shear flow Human vs porcine blood. International Journal of Artificial Organs 24(8): 545, August

Rey, J.L.; Delobel, J.; Claisse, J.F.; Quiret, J.C.; Bor, P.; Bernasconi, P., 1979: Severe pulmonary embolism and recurrent thrombophlebitis caused by hereditary antithrombin III deficiency. Severe pulmonary embolism with thrombosis of the inferior vena cava was observed in a 16 year old girl with no risk factors and treated successfully by fibrinolytic therapy. Secondarily, despite heparino-therapy, upper limb venous thrombosis occur...