Sillence M N, Etherton T D
CSIRO, Division of Tropical Animal Production, Rockhampton, Queensland, Australia.
J Anim Sci. 1991 Jul;69(7):2815-21. doi: 10.2527/1991.6972815x.
The present study was conducted to determine whether corticosteroids influence the inductive effect of growth hormone (GH) on plasma concentrations of insulin-like growth factor I (IGF-I). The first experiment was designed to determine the effects of corticosterone alone on basal concentrations of IGF-I. Rats were treated daily for 4 d with 0, 50, 100, 250, or 500 mg of corticosterone/kg of BW. There was a close positive relationship between the dose of steroid injected and plasma concentrations of corticosterone and a close negative relationship between plasma corticosterone and growth. Plasma concentrations of IGF-I showed a positive relationship to dose and plasma concentrations of corticosterone and a negative relationship to growth rate. In the second experiment, rats were treated daily for 21 d with either porcine growth hormone (10 mg of pGH/kg of BW), pGH plus corticosteroid, or vehicle. The dose of steroid administered was increased every 3 d until the mean weight gain of the group was zero. Animals treated with pGH alone gained significantly more weight than controls. This growth response was not impaired significantly by corticosterone acetate at doses up to 500 mg/kg of BW. The more potent corticosteroid, cortisone, arrested the growth of pGH-treated rats at a dose of 80 mg/kg of BW, however. Plasma concentrations of IGF-I were increased by pGH treatment (57%) and increased further by concurrent cortisone treatment (212%). In summary, corticosteroids increase plasma concentrations of IGF-I and enhance the inductive effect of pGH on this hormone despite their catabolic actions.
本研究旨在确定皮质类固醇是否会影响生长激素（GH）对胰岛素样生长因子I（IGF-I）血浆浓度的诱导作用。第一个实验旨在确定单独使用皮质酮对IGF-I基础浓度的影响。大鼠每天接受0、50、100、250或500毫克/千克体重的皮质酮处理，持续4天。注射的类固醇剂量与血浆皮质酮浓度之间存在密切的正相关，而血浆皮质酮与生长之间存在密切的负相关。IGF-I的血浆浓度与剂量和血浆皮质酮浓度呈正相关，与生长速率呈负相关。在第二个实验中，大鼠每天接受猪生长激素（10毫克/千克体重的pGH）、pGH加皮质类固醇或赋形剂处理，持续21天。每隔3天增加一次类固醇的给药剂量，直到该组的平均体重增加为零。单独接受pGH处理的动物体重增加明显多于对照组。高达500毫克/千克体重的醋酸皮质酮并未显著削弱这种生长反应。然而，更有效的皮质类固醇可的松在剂量为80毫克/千克体重时阻止了pGH处理大鼠的生长。pGH处理使IGF-I的血浆浓度增加（57%），同时使用可的松处理使其进一步增加（212%）。总之，尽管皮质类固醇具有分解代谢作用，但它们会增加IGF-I的血浆浓度，并增强pGH对该激素的诱导作用。
