Pascual M, Larralde J, Martínez J A
Department Physiology and Nutrition, University of Navarra, Spain.
Growth Dev Aging. 1995 Winter;59(4):181-91.
The acute organ-specific and metabolic actions of Insulin-like Growth Factor-I (IGF-I) and Growth Hormone (GH) were investigated in normal rats. Rats received a single subcutaneous injection of IGF-I (100 micrograms), GH (100 micrograms) or a combined treatment with IGF-I (100 micrograms) plus GH (100 micrograms) following a 2(2) factorial design. The acute treatment with IGF-I produced an increase in its plasma concentration along with a reduction in insulin levels. Plasma glucose and total cholesterol decreased in all treated groups as well as triglycerides in IGF-I treated animals as compared to controls. The rates of protein synthesis, measured by amino acid incorporation were not affected by any of these treatments in muscle or liver. However, GH treatment raised the rate of protein synthesis in the jejunum, while IGF-I treatment produced an increase in tibia protein synthesis rate. Negative interactions between GH and IGF were noted concerning tibia and jejunum protein formation. Thus, GH appeared to inhibit the response to IGF-I in bone, while IGF-I inhibited the response of the jejunum to GH administration. Also, liver cathepsin activity was reduced, while bone alkaline phosphase was increased by the GH treatment. Therefore, these results have demonstrated some acute organ-specific anabolic effects and interactions of IGF-I and GH on different aspects of metabolism in normal rats.
在正常大鼠中研究了胰岛素样生长因子-I（IGF-I）和生长激素（GH）的急性器官特异性及代谢作用。大鼠按照2×2析因设计接受单次皮下注射IGF-I（100微克）、GH（100微克）或IGF-I（100微克）加GH（100微克）的联合治疗。IGF-I的急性治疗使其血浆浓度升高，同时胰岛素水平降低。与对照组相比，所有治疗组的血浆葡萄糖和总胆固醇均降低，IGF-I治疗组动物的甘油三酯也降低。通过氨基酸掺入法测定的蛋白质合成速率在肌肉或肝脏中不受这些治疗的影响。然而，GH治疗提高了空肠中的蛋白质合成速率，而IGF-I治疗使胫骨蛋白质合成速率增加。在胫骨和空肠蛋白质形成方面，观察到GH与IGF之间存在负相互作用。因此，GH似乎抑制了骨骼对IGF-I的反应，而IGF-I抑制了空肠对GH给药的反应。此外，GH治疗降低了肝脏组织蛋白酶活性，而增加了骨碱性磷酸酶活性。因此，这些结果证明了IGF-I和GH对正常大鼠代谢不同方面的一些急性器官特异性合成代谢作用及相互作用。
