بررسی اثر کاتیون‌های فلزی V5+, W6+ , Zn2+ بر میزان ترشح انسولین و فعالیت آنزیم گلوکوکیناز در جزایر لانگرهانس جدا شده از موش صحرایی سالم و دیابتی

Background: Insulin dependant Diabetes Mellitus (IDDM) is associated with a reduction in production or secretion of insulin from pancreatic Islets. On the other hand increase in insulin secretion will result in destruction of islets that will lead to Diabetes .Therefore the factors that could regulate secretion will prevent the onset of diabetes . Glucose metabolism that commences with the glucokinase action is closely related to insulin secretion. The aim of this study is to survey the effect of eat ions Zn2+, V5+ and W5+ on insulin secretion and on the key enzyme, glucokinase, which is known to play an important role in insulin secretion . Methods: 20 single islets were seprated from pancreatic tissues of each normal and diabetic rats and placed in tubes containing perfusion medium . Method ions with different concentrations/ and controls were provided with each set of experiment . Insulin secretion were determined using IDMA method. Glucokinaes activity in homogenate supernatant of normal and diabetic rats was assayed by spectropho to metric methods. Results: the level of insulin concernlyation was shown to increase with vandate and tungsten treatment in normal and diabetic rats / and decreased by zinc .The effect of zinc on glucokinase activity was similarly reducing . Tungsten caused an increase in glucokinase activity (p<.001) while vandate showed no effect on the activity of enzyme .Conclusion: The inhibitory effect of zinc on insulin secretion and the enhancing effect of tungsten correlate closely with their effect on glucokinase activity. There for the effect in insulin secretion could be assumed to be via glucokinase activation or inhibition . The effect of vandate on insulin secretion my be through other mechanisms which is not yet clarified.