Open AccessGlucose release as a response to glucagon in rat hepatocyte culture: involvement of NO signaling
Author(s) -
Hassan Farghali,
Jiří Hodis,
N Kutinová-Canová,
Petr Potměšil,
Eva Kmonı́čková,
Zdeněk Zı́dek
Publication year - 2008
Publication title -
physiological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 70
eISSN - 1802-9973
pISSN - 0862-8408
DOI - 10.33549/physiolres.931232
Subject(s) - glucagon , glycogenolysis , glycogen phosphorylase , medicine , forskolin , endocrinology , glycogen synthase , phosphorylase kinase , chemistry , nitric oxide synthase , glycogen , glycogen branching enzyme , protein kinase a , signal transduction , hepatocyte , stimulation , nitric oxide , biology , phosphorylation , biochemistry , insulin , in vitro
Glucagon and α-adrenergic-induced glycogenolysis is realized viathe agonist/adenylyl cyclase/cAMP/protein kinase signalingpathway or via the activation of phosphorylase kinase by themobilized calcium that supports the inhibition of glycogensynthase, respectively. The role of nitric oxide (NO) in thisprocess has not been extensively studied. The present work wasdirected to the question whether NO is produced duringglucagon-induced glycogenolysis in rat hepatocyte in a similarway like α-adrenoceptor stimulation. Glycogen-rich hepatocytecultures were used. NO production (NO2-) was assessed underthe influence of glucagon, dibutyryl cyclic AMP (db-cAMP),forskolin, the nitric oxide synthase (NOS) inhibitors Nω-nitro-Larginine methyl ester (L-NAME) and aminoguanidine, and the NOdonor S-nitroso-N-acetyl penicillamine (SNAP). Inducible NOS(iNOS) mRNA was examined by reverse transcription-polymerasechain reaction. Glycogenolysis was followed up by estimation ofmedium glucose levels. The amount of glucose and NO2- released by glycogen-rich hepatocytes was increased as a result ofglucagon, db-cAMP, forskolin and SNAP treatments. iNOS geneexpression was upregulated by glucagon. Glycogenolysis thatoccurs through glucagon receptor stimulation involves NOproduction downstream of transduction pathways through anisoform of NO synthase. The present and previous studiesdocument possible involvement of NO signaling in glycogenolyticresponse to glucagon and adrenergic agonists in hepatocytes.