History and Objectives: Due to the importance of diabetes and its increasing prevalence and since this micro organs (Langerhans islets) are invaded by the immune system in insulin-dependent diabetes mellitus, it seemed essential to extract and purify Langerhans islets by different methods and then compare the products. Determining the insulin secretory pattern of the islets due to the effect of potassium and glucose is another aim of this research.

Materials and Methods: An experimental study was performed on rats. The animal was anesthetized and the common bile dust was cannulated and Hanex solution was injected into it immediately afterwards the pancreas was excised and immersed in Kerbs-Ringer-Bbicarbonate-Hepes solution. After adding collagenase, it was incubated at 37 degrees of centigrade. Purification was performed by handpicking under stereomicroscope and discontinuous method of sucrose and ficoll gradient. Perfusion of insulin secretion of the islets. The secreted insulin was measured by RIA and the number of islets yielded from each method and also the insulin content of the islets, yielded by each method, were statistically analyzed with t-test in contrast with other methods.

Results: The number of islets from handpicking methods, sucrose gradient and ficoll gradient were 202±22.5, 84±14.5 and 230±26 respectively. Also the insulin content of the yielded islets from the above mentioned methods were in order: 106±7.6, 49±13 and 210±17 MU/10 islets (P<0.0001). Insulin secretory pattern was monophasic, when affected by potassium and biphasic due to the effect of glucose.

Conclusion: Purification of the isles by ficoll is advantageous over the two other methods both quantitatively and qualitatively. Also, the insulin secretory pattern due to the effects of glucose and potassium is biphasic and monophasic respectively. Insulin release is probably due to depolarization of the cytoplasmic membrane of beta cells of the islets and further research in this field is recommended.