Gröne H J, Neumann P, Fuchs E
Department of Pathology, University of Göttingen, FRG.
Miner Electrolyte Metab. 1992;18(2-5):256-63.
Human insulin-like growth factor I (IGF-I) is a growth and differentiating factor produced by various adult and fetal tissues. In the kidney, it has been linked to the proliferative response of renal tubular and glomerular cells, following unilateral or partial nephrectomy, in acromegaly, in diabetes mellitus and in glomerulonephritis. To gain insight into the potential effects of IGF-I in human kidney, a quantitative analysis of IGF-I-binding sites was performed in fetal and adult tissue using 125I-IGF-I. The ligand consistently labelled renal cortex, medulla, and glomeruli while renal vessels were not uniformly marked. The highest affinity of binding sites was found in glomeruli (adult kidneys: Kd 24.7 +/- 5.1 pM; Bmax 5.2 +/- 0.5 fmol/mg tissue equivalent (TE); n = 4; fetal kidneys: Kd 17.0 +/- 2.5 pM; Bmax 4.5 +/- 0.7 fmol/mg TE; n = 4) and cortical tubules, while vessels and renal medulla (adult kidneys: kd 47 +/- 3.9 pM, Bmax 2.6 +/- 0.3 fmol/mg TE; n = 4; fetal kidneys: kd 41.6 +/- 9.2 pM, Bmax 3.5 +/- 0.4 fmol/mg TE; n = 3) had only about half the affinity of binding and a significantly reduced maximal capacity. The strong binding of 125I-IGF-I to glomeruli supports the view that IGF-I may be involved in modulating glomerular structure and function. Fetal renal growth may depend on the action of IGF-I on glomerular cells and tubular epithelia of the kidney.
人胰岛素样生长因子I（IGF-I）是一种由各种成人和胎儿组织产生的生长和分化因子。在肾脏中，它与单侧或部分肾切除术后、肢端肥大症、糖尿病和肾小球肾炎中肾小管和肾小球细胞的增殖反应有关。为了深入了解IGF-I在人肾脏中的潜在作用，使用125I-IGF-I对胎儿和成人组织中的IGF-I结合位点进行了定量分析。该配体始终标记肾皮质、髓质和肾小球，而肾血管标记不统一。结合位点的最高亲和力出现在肾小球（成人肾脏：解离常数（Kd）24.7±5.1皮摩尔；最大结合容量（Bmax）5.2±0.5飞摩尔/毫克组织当量（TE）；n = 4；胎儿肾脏：Kd 17.0±2.5皮摩尔；Bmax 4.5±0.7飞摩尔/毫克TE；n = 4）和皮质肾小管，而血管和肾髓质（成人肾脏：Kd 47±3.9皮摩尔，Bmax 2.6±0.3飞摩尔/毫克TE；n = 4；胎儿肾脏：Kd 41.6±9.2皮摩尔，Bmax 3.5±0.4飞摩尔/毫克TE；n = 3）的结合亲和力仅约为一半，且最大容量显著降低。125I-IGF-I与肾小球的强结合支持了IGF-I可能参与调节肾小球结构和功能的观点。胎儿肾脏生长可能取决于IGF-I对肾小球细胞和肾小管上皮细胞的作用。
