title: Mediation of protein kinase C zeta in mu-opioid receptor activation for increase of glucose uptake into cultured myoblast C2C12 cells.
abstract: The present study is designed to investigate the role of atypical protein kinase C (PKC) in the signaling of mu-opioid receptors (MOR) for glucose uptake in myoblast C(2)C(12) cells. Loperamide enhanced the uptake of radioactive deoxyglucose into C(2)C(12) cells in a concentration-dependent manner that was abolished in cells pre-incubated with GF109203X at concentrations sufficient to block PKC. Inhibition of the atypical zeta (zeta) isoform of PKC using myristoylated PKC pseudosubstrate resulted in a concentration-dependent decrease of loperamide-stimulated glucose uptake into C(2)C(12) cells. In addition, loperamide elicited the phosphorylation of PKC-zeta in C(2)C(12) cells in a concentration-dependent manner that was abolished by pretreatment with naloxonazine at concentrations sufficient to block MOR. These results suggest the mediation of PKC-zeta in MOR signaling for glucose uptake in C(2)C(12) cells. Activation of PKC-zeta by MOR stimulation is highly relevant to the search for therapeutic targets for glucose transport in insulin-sensitive tissues.
authors.affiliation: Graduate Institute of Basic Medical Science, College of Medicine, China Medical University, Taichung City 40401, Taiwan, ROC.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Yang
authors.forename: I-Min
authors.initials: IM
authors.lastname: Liu
authors.forename: Hung-Tsung
authors.initials: HT
authors.lastname: Wu
authors.forename: Juei-Tang
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002250:Carbon Radioisotopes; D002460:Cell Line; D003847:Deoxyglucose / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008139:Loperamide / Q000008:administration & dosage / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D032448:Myoblasts, Skeletal / Q000378:metabolism*; D009270:Naloxone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000099221:Protein Kinase C zeta
chemical_list: D002250:Carbon Radioisotopes; D003847:Deoxyglucose; D004791:Enzyme Inhibitors; D005947:Glucose; D007211:Indoles; D008139:Loperamide; D008301:Maleimides; D009270:Naloxone; D009292:Narcotic Antagonists; D011493:Protein Kinase C; D017450:Receptors, Opioid, mu; D000099221:Protein Kinase C zeta; C034643:naloxonazine; C070515:bisindolylmaleimide I