ENDOCRINE EXOCRINE INTERMEDIATE CELLS IN STREPTOZOTOCIN-TREATED INS-IFN-GAMMA TRANSGENIC MICE/

To trace the ontogeny of beta cell regrowth in adult transgenic mice t hat produce interferon-gamma in the islets (ins-IFN-gamma), their exis ting beta cells were depleted by treatment with high doses of streptoz otocin (STZ). Initially, beta cell necrosis and degranulation were app arent in STZ-treated mice of both the BALB/c and the ins-IFN-gamma tra nsgenic strains. The newly emerging transitional cells were then chara cterized by ultra-structural analysis. Interestingly, transitional cel ls harboring both exocrine and endocrine granules appeared frequently in ins-IFN-gamma transgenics after high-dose STZ treatment. New beta c ells were produced primarily by the formation of new islets from the s mall pancreatic ducts. beta cell regeneration in the ins-IFN-gamma tra nsgenic mouse model is thus explained primarily by the budding of new islets from the ducts with acinar cells as possible precursors of isle t cells.