Kobayashi S, Nogami H, Ikeda T
Department of Medicine, NTT (Nippon Telegraph and Telephone) Izu Teishin Hospital, Shizuoka, Japan.
Kidney Int. 1995 Jul;48(1):65-71. doi: 10.1038/ki.1995.268.
The effects of growth hormone (GH) and fasting on renal insulin-like growth factor-I (IGF-I) and IGF-binding proteins (IGFBP)-1, -2, -3, -4, -5 were examined in spontaneous dwarf rats (SDR) which have a complete and specific lack of GH among pituitary hormones. Renal expression of the mRNA which encodes IGF-I was reduced in these rats, and IGFBP-1 and IGFBP-4 were found to be elevated. Administration of GH restored expression of IGF-I and IGFBP-1 mRNA, suggesting that GH is, among other pituitary hormones, more specifically associated with renal expression of these genes. The elevation in the IGFBP-4 mRNA level, however, was not attenuated by GH administration, indicating that this hormone may not be directly related to the regulation of expression of this gene. Fasting for 48 hours resulted in a reduction of IGF-I mRNA and an increase in IGFBP-1 mRNA in SDRs as well as in normal rats, suggesting that a cause other than a reduced serum GH is responsible for these fasting-induced changes. Fasting resulted in little change in levels of other IGFBP-2, -3, -4, -5 mRNAs. When these results were compared with those obtained using liver, IGFBP mRNA expression was shown to be regulated differently in different tissues. Based on our finding that IGFBP-1 modulates the mitogenic action of IGF-I, a full understanding of nutrition-related growth processes in the kidney must take this relationship into consideration as well as that which exists between GH and IGF-I.
在垂体激素中完全且特异性缺乏生长激素（GH）的自发性侏儒大鼠（SDR）中，研究了GH和禁食对肾胰岛素样生长因子-I（IGF-I）及IGF结合蛋白（IGFBP）-1、-2、-3、-4、-5的影响。这些大鼠中编码IGF-I的mRNA的肾表达降低，且发现IGFBP-1和IGFBP-4升高。给予GH可恢复IGF-I和IGFBP-1 mRNA的表达，表明在其他垂体激素中，GH与这些基因的肾表达更具特异性关联。然而，给予GH并未减弱IGFBP-4 mRNA水平的升高，这表明该激素可能与该基因表达的调节无直接关系。禁食48小时导致SDR以及正常大鼠中IGF-I mRNA减少和IGFBP-1 mRNA增加，这表明除血清GH降低外的其他原因导致了这些禁食诱导的变化。禁食对其他IGFBP-2、-3、-4、-5 mRNA水平影响不大。当将这些结果与使用肝脏获得的结果进行比较时，发现IGFBP mRNA表达在不同组织中的调节方式不同。基于我们发现IGFBP-1调节IGF-I的促有丝分裂作用，对肾脏中与营养相关的生长过程的全面理解必须考虑到这种关系以及GH与IGF-I之间存在的关系。
