RELATIVE INCREASE IN INSULIN-LIKE GROWTH FACTOR-I MESSENGER-RIBONUCLEIC-ACID LEVELS IN COMPENSATORY RENAL HYPERTROPHY
RELATIVE INCREASE IN INSULIN-LIKE GROWTH FACTOR-I MESSENGER-RIBONUCLEIC-ACID LEVELS IN COMPENSATORY RENAL HYPERTROPHY
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DOI：
10.1210/endo-120-2-718
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发表时间：
1987-02-01
期刊：
影响因子：
4.8
通讯作者：
MELMED, S
中科院分区：
文献类型：
--
作者：
FAGIN, JA;MELMED, S
免疫反应性胰岛素样生长因子I（IGF-I）最近已被证明在多个组织，包括肝，肾，肺，睾丸和脑。垂体切除大鼠的组织IGF-I水平被GH升高。为了研究组织IGF-I的产生是否受局部和全身影响的调节，我们研究了单侧肾切除术后发生的肾脏代偿性肥大中大鼠肾脏IGF-I基因的表达。用[32 P]IGF-I小鼠cDNA探针对肾脏多聚（A）RNA进行北方分析，发现存在大小为1.3倍的mRNA种类。肾脏poly（A）RNA的斑点杂交显示，相对于对照假手术大鼠的水平，肾切除动物的肾脏中IGF-I mRNA被诱导5- 6倍。这种诱导在手术后24小时出现，并在手术后持续至少7天。肾放射免疫测定IGF-I含量也增加了73%，肾切除动物，虽然这是只明显的手术后第四天。相比之下，肝脏IGF-I mRNA水平在实验和对照动物中相当，表明IGF-I诱导对正在进行代偿性生长的组织具有特异性。血清IGF-I和GH水平在肾切除和对照动物的实验期间没有改变。因此，这些研究证实IGF-I在肾脏中合成，并且经历代偿性生长的肾脏具有增加的IGF-I mRNA水平。这种现象的发生独立于GH分泌的变化，表明旁分泌或自分泌因子参与了肾脏IGF-I产生的控制。
Immunoreactive insulin-like growth factor I (IGF-I) has recently been demonstrated in multiple tissues, including liver, kidney, lung, testes, and brain. Tissue IGF-I levels in hypophysectomized rats are elevated by GH. To examine whether tissue IGF-I production is regulated by local as well as systemic influences, we studied rat kidney IGF-I gene expression in renal compensatory hypertrophy occurring after unilateral nephrectomy. Northern analysis of kidney poly(A) RNA probed with [32P]IGF-I mouse cDNA revealed the presence of a mRNA species 1.3 kilobases in size. Dot hybridization of kidney poly(A) RNA showed that IGF-I mRNA was induced 5- to 6-fold in the kidneys of nephrectomized animals relative to levels in control sham-operated rats. This induction was present 24 h after surgery and continued for at least 7 days after the operation. Kidney radioimmunoassayable IGF-I content was also increased 73% in nephrectomized animals, although this was only apparent on the fourth day after surgery. In contrast, liver IGF-I mRNA levels were comparable in both experimental and control animals, suggesting that the IGF-I induction was specific to the tissue undergoing compensatory growth. Serum IGF-I and GH levels were not altered in nephrectomized and control animals for the duration of the experiments. These studies, therefore, confirm that IGF-I is synthesized in the kidney, and that kidneys undergoing compensatory growth have increased levels of IGF-I mRNA. This phenomenon occurs independently of changes in GH secretion, indicating that paracrine or autocrine factors are involved in the control of renal IGF-I production.