Morphology of the endocrine pancreas in cyclosporine-treated glucose-intolerant Wistar rats.

The toxic effect of Cyclosporin A (CS-A) (1.25-50.0 mg/kg body weight) on the endocrine pancreas of Wistar rats was morphologically investigated. The treatment of animals with CS-A doses above 5 mg/kg for 2 weeks resulted in a disturbed glucose tolerance, a reduced B-cell volume density and degranulation, vacuolization and decreased mitotic activity of the B-cells. After withdrawal of the drug the impaired parameters were stepwise normalized, starting with regranulation of pancreatic B-cells, followed by a stimulation of mitotic activity, and increase of B-cell volume density. When continuing the CS-A treatment with doses lower than 5.0 mg/kg for longer periods we observed a decreased body weight gain and reduced pancreatic insulin content.