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Studies on the cell‐cycle dependency of the actions of insulin‐like growth factor‐I in Balb/c 3T3 cells
Author(s) -
Kojima Itaru,
Kitaoka Masafumi,
Ogata Etsuro
Publication year - 1990
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041430318
Subject(s) - pertussis toxin , 3t3 cells , cell cycle , autophosphorylation , biology , microbiology and biotechnology , diacylglycerol kinase , growth factor , receptor , cell , biochemistry , g protein , transfection , phosphorylation , protein kinase c , protein kinase a , gene
Abstract The present study was conducted to determine the cell‐cycle dependency of various actions of IGF‐I in Balb/c 3T3 cells. When autophosphorylation of the IGF‐I receptor was determined in [ 32 P]‐labelled cells, IGF‐I increased radioactivity in a 100 K‐Da phosphoprotein, presumably β‐subunit of the IGF‐I receptor, both in quiesent and in primed competent cells. Likewise, IGF‐I stimulated uptake of [ 3 H]deoxyglucose independent of the cell cycle. In contrast, IGF‐I increased calcium entry, radioactivity in [ 3 H]diacylglycerol, and [ 3 H]thymidine incorporation in primed competent cells while these reactions were not induced by IGF‐I in quiescent cells. The latter three reactions were attenuated when cells were pretreated with pertussis toxin. These results indicate that some, but not all, of the actions of IGF‐I are dependent on the cell cycle in Balb/c 3T3 cells. They also suggest that a pertussis‐toxin‐sensitive G protein may be involved in the cellcycle‐dependent actions of IGF‐I.