Linebaugh B E, Rillema J A
Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201.
Mol Cell Endocrinol. 1987 Aug;52(3):227-33. doi: 10.1016/0303-7207(87)90048-7.
The role of insulin in stimulating metabolic processes in MCF-7 cells was studied in cells synchronized at the G1:S interphase of the cell cycle using hydroxyurea. Cells released from the hydroxyurea block progressed through one S-phase of the cell cycle when insulin was absent from the medium. When free insulin was present the cells continued through more than one S-phase. Since cells accumulate at G0 in serum- and hormone-free conditions it is apparent that insulin has an essential action in the MCF-7 cells between the G0 and S-phase of the cell cycle. Insulin is also known to stimulate the incorporation of [3H]leucine into a pH 4.6 precipitable phosphoprotein fraction in the MCF-7 cells. Insulin was shown to express this action, even when the cells were maintained at the G1:S interphase with hydroxyurea. Insulin is thus able to effect a differentiative action, i.e. a stimulation of phosphoprotein synthesis, under conditions where insulin's effect on [3H]thymidine incorporation into DNA is prevented.
使用羟基脲使细胞周期同步于G1:S间期，研究胰岛素在刺激MCF - 7细胞代谢过程中的作用。当培养基中不存在胰岛素时，从羟基脲阻滞中释放的细胞经历细胞周期的一个S期。当存在游离胰岛素时，细胞继续经历不止一个S期。由于细胞在无血清和无激素条件下积聚于G0期，显然胰岛素在MCF - 7细胞的细胞周期G0期和S期之间具有重要作用。已知胰岛素还能刺激[3H]亮氨酸掺入MCF - 7细胞中pH 4.6可沉淀的磷蛋白组分。即使细胞用羟基脲维持在G1:S间期，胰岛素也显示出这种作用。因此，在胰岛素对[3H]胸苷掺入DNA的作用被阻断的条件下，胰岛素能够产生分化作用，即刺激磷蛋白合成。
