The objectives of this research are two-fold. Inbred mice provide four distinct genes whose expressions produce either hyperplastic or pathological changes in the endocrine or exocrine pancreas. We propose, first, to develop cell culture systems for the study of the biochemical expression of the known mutant genes affecting the pancreas, and, second, to establish lines of functional pancreatic endocrine cells from both normoglycemic and mutant strains of the inbred mouse for the purpose of developing methods of cell-replacement therapy for human patients with pancreatic deficiencies.