Direct streptozotocin toxicity on dispersed mouse islet cells determined by [51]Cr-release.

Dispersed islet cells were prepared from collagenase-isolated lean mouse pancreatic islets by Dispase-II and subsequent mechanical treatment in calcium depleted media. An average yield of 600 cells per islet was obtained, 84% of the cells being beta-cells. Cells were incubated with radioactive chromium as a marker of cell viability. Optimal labelling of 1--2 cpm per cell was obtained by incubating 10(5) cells with 10(6) cpm of [51]Cr for 90 min. When islet cells were incubated with streptozotocin, this drug induced [51]Cr-release after a lag time of 2--4 hours. Furthermore, a positive correlation between streptozotocin concentrations and [51]Cr-release was found. This assay of cytotoxicity was highly reproducible and might be applicable in the study of other beta-cell damaging agents or autoimmune phenomena in the pathogenesis of diabetes.