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Insulin Induces Intracellular Calcium Transients through Activation of NADPH Oxidase in Myotubes
Author(s) -
Espinosa Berta Alejandra,
Hidalgo Cecilia,
Jaimovich Enrique
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1047.3
Subject(s) - nadph oxidase , apocynin , calcium in biology , calcium , microbiology and biotechnology , reactive oxygen species , chemistry , ryanodine receptor , calcium signaling , protein kinase c , intracellular , biochemistry , signal transduction , biology , organic chemistry
In cultured myotubes, insulin triggers intracellular calcium increases measured as fluo‐3 fluorescence. We occasionally see a fast calcium transient (first signal), but around 80s later, myotubes produce a second, oscillatory calcium signal. It is known that insulin signaling involves reactive oxygen species (ROS) production in many cell types. The aim of this work is to study the role of ROS, via NADPH oxidase activation in the mechanism that generates the second intracellular calcium increase. The second calcium signal was inhibited by two drugs (xestospongin B and U73122) that interfere with IP 3 pathway. Calcium increase was also blocked by bisindolylmaleimide (BIM), and rottlerin, both inhibitors of protein kinase C. Using the probe 2′, 7′‐dichlorofluorescein diacetate (DCFH‐DA) we showed that insulin induced ROS production in myotubes. Both calcium increase and ROS production were abolished by diphenyl iodonium (DPI), NADPH oxidase inhibitor apocynin and siRNA against p47 phox ; a regulatory subunits of NADPH oxidase. These results point to a role of insulin‐induced ROS in triggering calcium increase via IP3 receptor. NADPH oxidase is probably activated by a PKC and then ROS modulate IP3 receptors to increase intracellular calcium. FONDAP 15010006