TY - JOUR
T1 - Insulin and cyclic AMP act at different levels on transcription of the L-type pyruvate kinase gene
AU - Cuif, Marie Hélène
AU - Doiron, Bruno
AU - Kahn, Axel
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1997/11/3
Y1 - 1997/11/3
N2 - We previously demonstrated that, in hepatocytes in primary culture, the role of insulin on induction of L-type pyruvate kinase (L-PK) gene expression was mainly to induce glucokinase synthesis, needed for glucose phosphorylation to glucose 6-phosphate. However, we show here that when hepatocytes have been isolated from rats starved for 72 h, glucose and constitutive glucokinase expression was not sufficient to fully stimulate the L-PR promoter, low insulin concentrations being still required. In addition, activation remains sensitive to cAMP inhibition, but cannot he reproduced in the absence of insulin by a competitive cAMP antagonist. We propose that both insulin and cAMP act on expression of the L-PK gene at, at least, two levels: positive and negative regulation of glucokinase gene expression, and more downstream levels.
AB - We previously demonstrated that, in hepatocytes in primary culture, the role of insulin on induction of L-type pyruvate kinase (L-PK) gene expression was mainly to induce glucokinase synthesis, needed for glucose phosphorylation to glucose 6-phosphate. However, we show here that when hepatocytes have been isolated from rats starved for 72 h, glucose and constitutive glucokinase expression was not sufficient to fully stimulate the L-PR promoter, low insulin concentrations being still required. In addition, activation remains sensitive to cAMP inhibition, but cannot he reproduced in the absence of insulin by a competitive cAMP antagonist. We propose that both insulin and cAMP act on expression of the L-PK gene at, at least, two levels: positive and negative regulation of glucokinase gene expression, and more downstream levels.
KW - Cyclic AMP
KW - Glucose
KW - Insulin
KW - L-type pyruvate kinase
KW - Transcriptional control
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U2 - 10.1016/S0014-5793(97)01260-X
DO - 10.1016/S0014-5793(97)01260-X
M3 - Article
C2 - 9395079
AN - SCOPUS:0030697989
VL - 417
SP - 81
EP - 84
JO - FEBS Letters
JF - FEBS Letters
SN - 0014-5793
IS - 1
ER -