Díez J, Laviades C, Martínez E, Gil M J, Monreal I, Fernández J, Prieto J
Department of Internal Medicine, University of Navarra, Pamplona, Spain.
J Hypertens. 1995 Mar;13(3):349-55.
It was reported previously that circulating insulin-like growth factor I levels are abnormally elevated in patients with essential hypertension and left ventricular hypertrophy. Tissue availability of the factor depends on the distribution of the circulating bound factor between its high- and low-molecular mass binding proteins, only the latter being able to cross the endothelium. The aim of this study was to investigate whether the presence of the different serum binding proteins is altered in patients with essential hypertension and left ventricular hypertrophy.
The study was performed in 30 never-treated patients with essential hypertension and 30 age- and sex-matched normotensive subjects. Patients were separated into two groups according to the presence or the absence of echocardiographically determined left ventricular hypertrophy.
Plasma insulin-like growth factor I levels were determined by specific radioimmunoassay. The different molecular forms of its serum binding proteins were analysed by Western blotting using [125I]-labelled insulin-like growth factor I. A densitometric scanning of the blots was performed to analyse the quantitative relationships between the different forms of binding proteins.
Insulin-like growth factor I levels were significantly higher in the hypertensive patients with than in the hypertensive patients without left ventricular hypertrophy or in the normotensive subjects. Compared with the normotensive subjects, both hypertensive patients subgroups exhibited increased high-molecular mass binding protein type 3 and decreased low-molecular mass binding proteins types 1 and 2. However, changes in the binding proteins were more marked in the hypertensive patients without than in the hypertensive patients with left ventricular hypertrophy. Accordingly, the ratio of low- to high-molecular mass binding proteins (an index of insulin-like growth factor I bioavailability) was higher in the hypertensive patients with than in the hypertensive patients without left ventricular hypertrophy.
These results show that the distribution of the molecular forms of serum insulin-like growth factor binding proteins is altered in patients with essential hypertension, independently of insulin-like growth factor I levels. This suggests that regulation of the binding proteins is abnormal in essential hypertension. Whether the tissue availability of circulating insulin-like growth factor I is higher in hypertensive patients with than in hypertensive patients without left ventricular hypertrophy merits further investigation.
先前有报道称，原发性高血压和左心室肥厚患者循环中的胰岛素样生长因子I水平异常升高。该因子的组织可用性取决于循环中结合因子在其高分子量和低分子量结合蛋白之间的分布，只有后者能够穿过内皮。本研究的目的是调查原发性高血压和左心室肥厚患者中不同血清结合蛋白的存在是否发生改变。
该研究纳入了30例未经治疗的原发性高血压患者和30例年龄及性别匹配的血压正常受试者。根据超声心动图确定的左心室肥厚情况，将患者分为两组。
采用特异性放射免疫分析法测定血浆胰岛素样生长因子I水平。使用[125I]标记的胰岛素样生长因子I，通过蛋白质印迹法分析其血清结合蛋白的不同分子形式。对印迹进行光密度扫描，以分析不同形式结合蛋白之间的定量关系。
有左心室肥厚的高血压患者的胰岛素样生长因子I水平显著高于无左心室肥厚的高血压患者或血压正常受试者。与血压正常受试者相比，两个高血压患者亚组的高分子量结合蛋白3型均增加，低分子量结合蛋白1型和2型均减少。然而，无左心室肥厚的高血压患者中结合蛋白的变化比有左心室肥厚的高血压患者更明显。因此，有左心室肥厚的高血压患者中低分子量与高分子量结合蛋白的比值（胰岛素样生长因子I生物利用度指标）高于无左心室肥厚的高血压患者。
这些结果表明，原发性高血压患者血清胰岛素样生长因子结合蛋白的分子形式分布发生改变，与胰岛素样生长因子I水平无关。这表明原发性高血压中结合蛋白的调节异常。有左心室肥厚的高血压患者循环中的胰岛素样生长因子I的组织可用性是否高于无左心室肥厚的高血压患者，值得进一步研究。
