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Vanadate potentiates the glycogenic action of insulin‐like growth factors on isolated diaphragm
Author(s) -
Vandorpe Greet,
Bollen Mathieu,
Van Herck Erik,
Bouillon Roger,
Stalmans Willy
Publication year - 1992
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 - 10.1016/0014-5793(92)81096-5
Subject(s) - vanadate , insulin , glycogen , glycogen synthase , medicine , in vivo , endocrinology , chemistry , mechanism of action , biology , biochemistry , in vitro , microbiology and biotechnology
Na 3 VO 4 (6.5 μmol/100 g rat weight), co‐injected with a trace amount of [ ??? C]glucose, increased within 15 min the incorporation of radiolabel in diaphragmal glycogen. After 2 h the vanadate‐induced increases were 12‐fold in the diaphragm and 7–8‐fold in heart and liver. In contrast, when added to isolated diaphragms for up to 1 h, vanadate (0.1–5 mM) had no effect on the synthesis of glycogen from 5 mM glucose. In search of a putative mediator of vanadate's action in vivo, insulin and the insulin‐like growth factors (IGFs) were considered. Their plasma concentration was not affected by vanadate treatment. In isolated diaphragms, 1 mM vanadate did not potentiate insulin‐induced glycogen synthesis, but it caused a several‐fold increase in glycogen synthesis in the presence of concentrations of IGF‐I which, alone, had no effect. A similar synergism occurred between vanadate and IGF‐II. We propose that the glycogenic action of vanadate in vivo, at least in some tissues, involves a potentiation of the action of IGF‐I.