Kojima I, Kitaoka M, Ogata E
Fourth Department of Internal Medicine, University of Tokyo School of Medicine, Japan.
J Cell Physiol. 1990 Jun;143(3):529-33. doi: 10.1002/jcp.1041430318.
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 [32P]-labelled cells, IGF-I increased radioactivity in a 100 K-Da phosphoprotein, presumably beta-subunit of the IGF-I receptor, both in quiescent and in primed competent cells. Likewise, IGF-I stimulated uptake of [3H]deoxyglucose independent of the cell cycle. In contrast, IGF-I increased calcium entry, radioactivity in [3H]diacylglycerol, and [3H]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 cell-cycle-dependent actions of IGF-I.
本研究旨在确定胰岛素样生长因子-I（IGF-I）在Balb/c 3T3细胞中各种作用的细胞周期依赖性。当在[32P]标记的细胞中测定IGF-I受体的自磷酸化时，IGF-I在静止细胞和预致敏的感受态细胞中均增加了100 kDa磷蛋白（可能是IGF-I受体的β亚基）中的放射性。同样，IGF-I刺激[3H]脱氧葡萄糖的摄取，且不依赖于细胞周期。相比之下，IGF-I增加了预致敏感受态细胞中的钙内流、[3H]二酰甘油中的放射性以及[3H]胸苷掺入，而在静止细胞中IGF-I不会诱导这些反应。当细胞用百日咳毒素预处理时，后三种反应减弱。这些结果表明，在Balb/c 3T3细胞中，IGF-I的某些作用（但不是全部）依赖于细胞周期。它们还表明，一种对百日咳毒素敏感的G蛋白可能参与了IGF-I的细胞周期依赖性作用。
