Welsh N, Eizirik D L, Bendtzen K, Sandler S
Department of Medical Cell Biology, Uppsala University, Sweden.
Endocrinology. 1991 Dec;129(6):3167-73. doi: 10.1210/endo-129-6-3167.
The aim of this study was to characterize the dynamics and functional relevance of interleukin-1 beta (IL-1 beta)-induced nitric oxide production in isolated pancreatic islets. Thus, islets were isolated from adult rats, precultured for 3-5 days in medium RPMI-1640 plus 10% fetal calf serum, and then exposed to IL-1 beta for different time periods, after which islet nitrite production and aconitase activity were determined. IL-1 beta (5 ng/ml) did not increase islet nitrite production during the first hour of incubation. Moreover, the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (Meth-arg; 5 mM) failed to prevent the initial (90 min) IL-1 beta-induced increase in islet insulin release. After 4, 7, and 24 h, however, nitrite production was increased by 50%, 93%, and 139%, respectively. Islet aconitase activity and glucose oxidation rates were decreased by 70% after incubation for 24 h with IL-1 beta. Both Meth-arg and N alpha-p-tosyl-L-lysine chloromethyl ketone (0.1 mM), a protease inhibitor, could completely counteract the IL-1 beta-induced increases in nitrite production and inhibition of aconitase activity and glucose oxidation rates. In a separate series of experiments, islets were incubated for 60 min with or without IL-1 beta and the RNA synthesis inhibitor actinomycin-D (5 micrograms/ml) and subsequently incubated for another 9 h without any additions. The presence of actinomycin-D during the 1-h IL-1 beta incubation period prevented the IL-1 beta-induced rise in nitrite production and the IL-1 beta-induced inhibition of aconitase activity and insulin release. It is concluded that IL-1 beta-induced nitric oxide production is a late event which requires gene transcription and does not mediate the initial stimulatory effects of IL-1 beta on beta-cell function. However, the gradually augmented rate of nitric oxide production may inhibit the enzyme aconitase, leading to a suppressed mitochondrial activity and a defective insulin release in response to nutrient secretagogues.
本研究的目的是描述白细胞介素-1β（IL-1β）诱导的一氧化氮在分离的胰岛中产生的动力学及功能相关性。因此，从成年大鼠分离胰岛，在含10%胎牛血清的RPMI-1640培养基中预培养3至5天，然后在不同时间段用IL-1β处理，之后测定胰岛亚硝酸盐产生量和乌头酸酶活性。在孵育的第一小时，IL-1β（5 ng/ml）未增加胰岛亚硝酸盐产生量。此外，一氧化氮合酶抑制剂NG-单甲基-L-精氨酸（甲基精氨酸；5 mM）未能阻止IL-1β诱导的胰岛胰岛素释放的初始（90分钟）增加。然而，在4、7和24小时后，亚硝酸盐产生量分别增加了50%、93%和139%。用IL-1β孵育24小时后，胰岛乌头酸酶活性和葡萄糖氧化率降低了70%。甲基精氨酸和蛋白酶抑制剂Nα-p-甲苯磺酰-L-赖氨酸氯甲基酮（0.1 mM）均可完全抵消IL-1β诱导的亚硝酸盐产生增加以及对乌头酸酶活性和葡萄糖氧化率的抑制。在另一系列实验中，胰岛在有或无IL-1β以及RNA合成抑制剂放线菌素-D（5 μg/ml）的情况下孵育60分钟，随后在无任何添加物的情况下再孵育9小时。在1小时的IL-1β孵育期间存在放线菌素-D可阻止IL-1β诱导的亚硝酸盐产生增加以及IL-1β诱导的对乌头酸酶活性和胰岛素释放的抑制。得出的结论是，IL-1β诱导的一氧化氮产生是一个晚期事件，需要基因转录，且不介导IL-1β对β细胞功能的初始刺激作用。然而，一氧化氮产生率的逐渐增加可能会抑制乌头酸酶，导致线粒体活性受到抑制以及对营养性促分泌剂的胰岛素释放存在缺陷。
