Streptozotocin-induced elevation of pancreatic taurine content and suppressive effect of taurine on insulin secretion.

The role of taurine in pancreatic insulin secretion was studied. The administration of the pancreato-toxic streptozotocin (STZ) induced a significant increase of pancreatic taurine content in ddY and CD-1 strains of mice in addition to a remarkable hyperglycemia which resulted from significant damage to the beta-cells of this organ. The increase in pancreatic taurine content was invariably observed under both the transient and the continuous hyperglycemic conditions induced by STZ. It was also shown by analysing lyophilized pancreatic sections that this elevation of taurine content in the pancreas induced by STZ was due to the rise of taurine level in the exocrine tissues, whereas that in the islets of Langerhans was not affected by STZ. On the other hand, the in vitro addition of taurine (1-10 mM) significantly suppressed the glucose-stimulated and Ca2+-dependent secretion of insulin (IRI) from the isolated islets of Langerhans without affecting the Ca2+-independent secretion of this hormone. Considering the results described above, it seems possible that the action site of taurine may be at the exterior of islet cells, perhaps at the cellular membranes of the islets of Langerhans. The present results suggest that pancreatic taurine may play a significant physiological role in the regulation of insulin secretion from the islets of Langerhans and of the serum level of glucose.