Gibas Magdalena, Torlińska Teresa, Madry Edyta, Maćkowlak Paweł
Department of Physiology, University of Medical Sciences, Poznań, Poland.
Med Sci Monit. 2004 Apr;10(4):BR109-14.
In this study we compared the effect of bradykinin (BK) on insulin-receptor interaction in rat adipose plasma membranes under normothermic and hypothermic conditions.
MATERIAL/METHODS: Plasma membranes were prepared and purified according to Havrankova and binding assay was performed using (125I) - insulin. The kinetic parameters of the hormone-receptor interaction were analyzed according to Scatchard using the LIGAND - Pc v.3.1 computer program. Additionally, we determined blood glucose and insulin concentrations. The results were interpreted statistically according to one-way analysis of variance (ANOVA).
Statistically significant changes mainly involved the low-affinity receptor class. In normothermic rats, BK provoked a decrease in insulin-receptor affinity (expressed as a drop in the association constant Ka2 by 64% and enhancement in the dissociation constant Kd2 by 215%), which was compensated by a 188% increase in the number of insulin receptors. Therefore, association constant times binding capacity remained unchanged. Administration of BK resulted in a decrease in serum glucose concentration by about 50%, while the insulin level did not change. Hypothermia lowered insulin concentration by 68% and elevated both the value of the association constant times binding capacity by 166% and the insulin-receptor affinity (Kd2 decreased by 71% and Ka2 increased markedly by about 771%). Administration of BK to hypothermic rats elevated blood insulinl level by180% and diminished (by about 64%) the value of association constant times binding capacity.
The results indicate that bradykinin plays a significant role in carbohydrate metabolism and may influence insulin-receptor interaction under both normothermic and hypothermic conditions.
在本研究中，我们比较了缓激肽（BK）在正常体温和低温条件下对大鼠脂肪细胞质膜中胰岛素受体相互作用的影响。
材料/方法：根据哈夫兰科娃的方法制备并纯化质膜，使用（125I） - 胰岛素进行结合测定。使用LIGAND - Pc v.3.1计算机程序根据斯卡查德分析激素 - 受体相互作用的动力学参数。此外，我们测定了血糖和胰岛素浓度。根据单因素方差分析（ANOVA）对结果进行统计学解释。
具有统计学意义的变化主要涉及低亲和力受体类别。在正常体温的大鼠中，BK引起胰岛素受体亲和力降低（表现为结合常数Ka2下降64%，解离常数Kd2升高215%），这通过胰岛素受体数量增加188%得到补偿。因此，结合常数乘以结合能力保持不变。给予BK导致血清葡萄糖浓度降低约50%，而胰岛素水平未改变。低温使胰岛素浓度降低68%，并使结合常数乘以结合能力的值升高166%，同时提高了胰岛素受体亲和力（Kd2降低71%，Ka2显著升高约771%）。给低温大鼠注射BK使血胰岛素水平升高180%，并使结合常数乘以结合能力的值降低（约64%）。
结果表明缓激肽在碳水化合物代谢中起重要作用，并且在正常体温和低温条件下都可能影响胰岛素受体相互作用。
