Premium
Insulin and cyclic AMP act at different levels on transcription of the L‐type pyruvate kinase gene
Author(s) -
Cuif Marie-Hélène,
Doiron Bruno,
Kahn Axel
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)01260-x
Subject(s) - pyruvate kinase , transcription (linguistics) , chemistry , gene , biochemistry , enzyme , glycolysis , linguistics , philosophy
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‐PK promoter, low insulin concentrations being still required. In addition, activation remains sensitive to cAMP inhibition, but cannot be 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.