Nakao M, Matsubara T, Sakamoto N
Third Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Heart Vessels. 1993;8(4):171-5. doi: 10.1007/BF01744738.
The effects of diabetes on myocardial glycogen metabolism in rats were examined and compared with those of fasting. Male Wistar rats were divided into three groups: controls, streptozotocin-induced diabetics, and one-week fasted. Isolated rat hearts were subjected to substrate-free 30-min Langendorff perfusion followed by 60-min working heart perfusion with glucose alone or in combination with insulin or insulin plus beta-hydroxybutyrate (BHB). Myocardial glycogen contents were determined before or 30 min after Langendorff perfusion, or 60 min after working heart perfusion. Before Langendorff perfusion, tissue glycogen concentrations in control, diabetic, and fasted hearts were 3.3 +/- 0.2, 10.0 +/- 0.9, and 5.7 +/- 0.5 (mg/g wet weight), respectively. In diabetic rats, the myocardial glycogen concentration was markedly decreased after working heart perfusion of any of the substrate combinations, even those with insulin and BHB. In contrast, myocardial glycogen in control or fasted rats was not reduced after the addition of glucose with insulin, and/or glucose with insulin and BHB. These results suggest that degradation of tissue glycogen occurs in isolated perfused hearts from diabetic rats, while a clearly different response is shown by fasted hearts.
研究了糖尿病对大鼠心肌糖原代谢的影响，并与禁食的影响进行了比较。雄性Wistar大鼠分为三组：对照组、链脲佐菌素诱导的糖尿病组和禁食一周组。将离体大鼠心脏进行30分钟无底物的Langendorff灌注，然后用单独的葡萄糖或与胰岛素或胰岛素加β-羟基丁酸（BHB）联合进行60分钟的工作心脏灌注。在Langendorff灌注前或灌注后30分钟，或工作心脏灌注后60分钟测定心肌糖原含量。在Langendorff灌注前，对照组、糖尿病组和禁食组心脏的组织糖原浓度分别为3.3±0.2、10.0±0.9和5.7±0.5（mg/g湿重）。在糖尿病大鼠中，无论使用哪种底物组合进行工作心脏灌注，即使是使用胰岛素和BHB的组合，心肌糖原浓度在灌注后均显著降低。相比之下，在对照组或禁食组大鼠中，添加胰岛素的葡萄糖和/或添加胰岛素和BHB的葡萄糖后，心肌糖原并未减少。这些结果表明，糖尿病大鼠离体灌注心脏中发生组织糖原降解，而禁食心脏表现出明显不同的反应。
