Trovati M, Massucco P, Mattiello L, Piretto V, Cavalot F, Mularoni E, Anfossi G
Department of Clinical and Biological Sciences of the University of Turin, San Luigi Gonzaga Hospital, Orbassano, Italy.
Diabetes. 1996 Jun;45(6):768-70. doi: 10.2337/diab.45.6.768.
To investigate whether the insulin-induced increase of guanosine-3',5'-cyclic monophosphate (cGMP) in human platelets is mediated by nitric oxide or is influenced by the nitric oxide precursor L-arginine, we measured cGMP in platelet-rich plasma obtained from healthy volunteers incubated for 3 min with human recombinant insulin (0, 240, 480, 960, and 1,920 pmol/l) both with and without 1) a 20-min incubation with the nitric oxide-synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) (50, 70, 100, and 1,000 micromol/l; n = 5 for each dose) and 2) a 20-min incubation with the nitric oxide precursor L-arginine (300 micromol/l; n = 6). In a first set of experiments, insulin induced a dose-dependent cGMP increase, from 9.8 +/- 0.8 to 45.6 +/- 5.5 pmol/10(9) platelets (P = 0.0001); in the presence of 1 mmol/l L-NMMA, this increase was blunted, cGMP being 8.9 +/- 1.4 and 11.1 +/- 2.2 pmol/10(9) platelets at 0 and 1,920 pmol/l insulin, respectively (NS). In the experiments with 70 and 100 micromol/l L-NMMA, the insulin effect on cGMP was inhibited, whereas 50 micromol/l L-NMMA did not blunt this insulin effect. In another set of experiments carried out to investigate the effects of L-arginine, insulin induced a dose-dependent cGMP increase, from 23.6 +/- 6.9 to 59.0 +/- 12.0 pmol/10(9) platelets (P = 0.0001); with L-arginine, basal cGMP values increased to 35.5 +/- 6.6 pmol/10(9) platelets (P = 0.05), and insulin maintained its ability to enhance dose-dependently cGMP values, which rose to 76.8 +/- 19.4 pmol/10(9) platelets (P = 0.003). This study carried out in human platelets demonstrates that the cGMP increase induced by insulin, which accounts for the antiaggregating effect of the hormone, is mediated by nitric oxide.
为了研究胰岛素诱导人血小板中鸟苷 - 3',5'-环磷酸（cGMP）增加是由一氧化氮介导还是受一氧化氮前体L - 精氨酸影响，我们检测了从健康志愿者获得的富含血小板血浆中的cGMP。将这些血浆分别与重组人胰岛素（0、240、480、960和1920 pmol / l）孵育3分钟，其中一部分在孵育前先分别与以下物质孵育20分钟：1）一氧化氮合酶抑制剂N(G)-单甲基 - L - 精氨酸（L - NMMA）（50、70、100和1000 μmol / l；每种剂量n = 5）；2）一氧化氮前体L - 精氨酸（300 μmol / l；n = 6）。在第一组实验中，胰岛素诱导cGMP呈剂量依赖性增加，从9.8±0.8 pmol / 10⁹血小板增加到45.6±5.5 pmol / 10⁹血小板（P = 0.0001）；在存在1 mmol / l L - NMMA的情况下，这种增加受到抑制，在胰岛素浓度为0和1920 pmol / l时，cGMP分别为8.9±1.4和11.1±2.2 pmol / 10⁹血小板（无统计学差异）。在使用70和100 μmol / l L - NMMA的实验中，胰岛素对cGMP的作用受到抑制，而50 μmol / l L - NMMA并未减弱胰岛素的这种作用。在另一组研究L - 精氨酸作用的实验中，胰岛素诱导cGMP呈剂量依赖性增加，从23.6±6.9 pmol / 10⁹血小板增加到59.0±12.0 pmol / 10⁹血小板（P = 0.0001）；加入L - 精氨酸后，基础cGMP值增加到35.5±6.6 pmol / 10⁹血小板（P = 0.05），并且胰岛素仍能维持其剂量依赖性增强cGMP值的能力，cGMP值上升到76.8±19.4 pmol / 10⁹血小板（P = 0.003）。这项在人血小板中进行的研究表明，胰岛素诱导的cGMP增加（这解释了该激素的抗聚集作用）是由一氧化氮介导的。
