Radojićić R, Cvijić G, Djordjević J, Djurasević S, Davidović V
Institute of Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Yugoslavia.
Comp Biochem Physiol C Pharmacol Toxicol Endocrinol. 1997 Jun;117(2):187-92. doi: 10.1016/s0742-8413(97)89893-3.
It was shown that hydrogen peroxide (H2O2) is a possible intracellular second messenger in specific insulin action. Because its concentration in the cell depends on the activity of both antioxidant enzymes and monoamine oxidase (MAO), we studied the influence of different insulin doses (0.4 and 4.0 IU/kg body mass, i.p., daily injected over 3 days) on the activity of MAO, types A and B, copper zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), and catalase in the rat brainstem. Chronic insulin treatment significantly increased Vmax of MAO-A and B activities (P < 0.05, P < 0.025, respectively) independent of the dose applied. CuZnSOD activity was also increased (P < 0.025), but only when higher dose of hormone was injected. However, insulin had the opposite effect on MnSOD and catalase causing a decrease in their activities (P < 0.005). The observed changes in the activities of the enzymes studied are possible compensations that potentially maintain an optimal H2O2 level in the brainstem, which might be important for insulin action.
研究表明，过氧化氢（H2O2）可能是特定胰岛素作用中的一种细胞内第二信使。由于其在细胞内的浓度取决于抗氧化酶和单胺氧化酶（MAO）的活性，我们研究了不同剂量胰岛素（0.4和4.0 IU/kg体重，腹腔注射，连续3天每天注射）对大鼠脑干中A型和B型MAO、铜锌超氧化物歧化酶（CuZnSOD）、锰超氧化物歧化酶（MnSOD）和过氧化氢酶活性的影响。慢性胰岛素治疗显著提高了MAO-A和MAO-B活性的Vmax（分别为P < 0.05，P < 0.025），且与所用剂量无关。CuZnSOD活性也有所增加（P < 0.025），但仅在注射较高剂量激素时出现。然而，胰岛素对MnSOD和过氧化氢酶具有相反的作用，导致它们的活性降低（P < 0.005）。所观察到的这些酶活性的变化可能是一种代偿机制，潜在地维持脑干中H2O2的最佳水平，这可能对胰岛素作用很重要。
