Metallothionein: in vitro induction with zinc and streptozotocin in pancreatic islets of mice.

Recently, this laboratory reported that the antioxidant metallothionein (MT) is constitutively expressed and significantly (p < 0.001) induced with zinc in pancreatic islets in vivo. Therefore, our aim was to study, whether MT can also be induced in vitro. We found that incubation of islets with either zinc sulfate (Zn) or streptozotocin (STZ) resulted in significant (p < 0.001) dose-dependent MT induction. With Zn a maximal induction was obtained with 0.1 mM reaching an induction index of 6.9 in C57BL/6 mice; a significant induction was also obtained in CD-1 mice. With subtoxic concentrations of STZ (2 and 4 mM) a significant induction was obtained in C57BL/6 mice. Thus, our in vivo data have been confirmed in vitro. Current investigations aim to analyse, whether MT induction can protect islets against toxicity mediated by reactive oxygen species (ROS).