男性心肌梗塞患者血浆性激素与红细胞胰岛素受体关系的临床及实验研究

RELATIONSHIP BETWEEN PLASMA SEX HORMONE AND INSULIN RECEPTOR IN MEN WITH MYOCARDIAL INFARCTION

本文对２０例男性心肌梗塞患者及与之配对的２０例正常人红细胞胰岛素受体进行检测，并根据Ｓｃａｔｃｈａｒｄ曲线计算受体的高、低亲和力位点数（Ｑ１、Ｑ２）及亲和力常数（Ｋ１、Ｋ２），同时测定了血浆性激素及胰岛素水平；并采用离体竞争结合的方法，研究性激素对胰岛素结合离体红细胞的影响。结果显示，心肌梗塞组Ｋ１、Ｑ２、Ｋ２低于正常对照组；直线相关分析发现，血浆睾酮与Ｋ１呈负相关，与Ｑ２呈正相关，胰岛素与Ｑ２呈负相关；竞争结合实验发现睾酮能减低胰岛素与受体的结合，而雌二醇未见影响。这提示，心肌梗塞患者的胰岛素抵抗可能与胰岛素受体数目减低及亲和力改变有关，睾酮可降低红细胞胰岛素受体的结合。

The aim of this study is to verify the relation between plasma sex hormone and insulin receptor in men with myocardial infarction. 20 male patients with myocardial infarction (2～18 months after AMI) matched with 20 normal subjects were investigated. Plasma estradiol, testosterone and insulin were determined ; insulin receptors of erythrocytes were indentified by means of 125 Ⅰ-l abeled insulin binding to erythrocytes while the affinity constant (K1, K2) and the number of receptors with different affinity and capacity (Q1, Q2)were calculated according to Scatchard's graphic method. Furthermore, insulin binding to erythrocytes in the presence of estradiol and testosterone was studied in vitro. The results showed that the number of insulin receptors with low affinity (Q2) on erythrocytes,K1 and K2 were lower in patients with myocardial infarction than controls; plasma testosterone positively and negatively correlated with Q2 and K1, respectively ;plasma insulin negatively correlated with Q2. In vitro study demonstrated that erythrocyte insulin binding was reduced by the addition of testosterone but not by estradiol. So it is concluded that the mechanism of insulin resistance in CHD might be associated with insulin receptor number and affinity abnormalities.Testosterone enhances insulin binding in vivo, and reduces insulin binding in vitro. Insulin resistance state might cause changes in testosterone action.