Houston B, O'Neill I E
Department of Cellular and Molecular Biology, AFRC Institute of Animal Physiology and Genetics Research, Roslin, Midlothian.
J Endocrinol. 1991 Mar;128(3):389-93. doi: 10.1677/joe.0.1280389.
Cultured chicken hepatocytes were used to investigate whether insulin and GH interact to regulate insulin-like growth factor-I (IGF-I) production in vitro. In the first set of experiments hepatocytes were preincubated for 6 h in hormone-free medium, and the effects of various combinations of insulin and GH on IGF-I production over the next 24 h were quantified by radioimmunoassay. Basal IGF-I production was 5.36 pg IGF-I/micrograms DNA and this was increased 1.31 +/- 0.13-fold (mean +/- S.E.M.) by insulin, 1.90 +/- 0.24-fold by GH and 4.46 +/- 0.68-fold by a combination of insulin and GH. These results demonstrate that insulin and GH interact synergistically to stimulate IGF-I production in vitro. The synergism with GH occurred at physiological concentrations of insulin with half-maximal stimulation occurring at an insulin concentration of 6 ng/ml. In hepatocytes which had been exposed to insulin immediately before the start of the experiment, the presence of insulin was no longer required for maximal stimulation of IGF-I production by GH. This in-vitro system will facilitate the study of the molecular basis of the interaction between insulin and GH.
利用培养的鸡肝细胞来研究胰岛素和生长激素（GH）是否在体外相互作用以调节胰岛素样生长因子-I（IGF-I）的产生。在第一组实验中，将肝细胞在无激素培养基中预孵育6小时，然后通过放射免疫测定法定量接下来24小时内胰岛素和GH的各种组合对IGF-I产生的影响。基础IGF-I产量为5.36 pg IGF-I/μg DNA，胰岛素使其增加了1.31±0.13倍（平均值±标准误），GH使其增加了1.90±0.24倍，胰岛素和GH的组合使其增加了4.46±0.68倍。这些结果表明，胰岛素和GH在体外相互协同作用以刺激IGF-I的产生。与GH的协同作用发生在胰岛素的生理浓度下，在胰岛素浓度为6 ng/ml时出现最大刺激的一半。在实验开始前立即暴露于胰岛素的肝细胞中，GH对IGF-I产生的最大刺激不再需要胰岛素的存在。这个体外系统将有助于研究胰岛素和GH之间相互作用的分子基础。
