Increased expression of a regenerating (reg) gene protein in neonatal rat pancreas treated with streptozotocin

We examined the expression of reg protein in neonatal rat pancreas treated with streptozotocin (STZ) by means of the immunohistochemical technique and northern blotting. Seven days after STZ injection, the plasma glucose levels in STZ-treated neonatal rats were significantly higher than those in control rats. Scattered distribution of reg protein in pancreatic islet cells was clearly observed in STZ-treated rats, but not in control rats. On the other hand, reg proteins was positively stained in the exocrine cells in both groups of rats. Northern blot analyses revealed that the expression of insulin mRNA markedly decreased in STZ-treated rat pancreas, but a significant increase in reg mRNA expression was recognized in the STZ-treated rat pancreas compared with that of control rats. Rats treated with STZ during the neonatal period have been used as a model of non-insulin-dependent diabetes mellitus (NIDDM) and beta cell regeneration. Thus, the increased reg gene expression in neonatal STZ-treated rat pancreas was therefore described for the first time, and thus would be a useful model for studying the relationship between NIDDM and beta cell regeneration or reg gene protein.