In this work, we have studied whether PrP, a protein found predominantly on the surface of neurons, could also exist in pancreatic endocrine cells. For this purpose, we have compared the expression of PrP mRNAs in insulin- (beta) and glucagon- (alpha) producing cells to that of neuronal and nonneuronal cells. We show that PrP mRNAs are expressed in all the beta and alpha cells tested at levels similar to those observed in neuronal cells. We also show that the expression of PrP is tightly regulated by hormones. Indeed, recombinant human growth hormone and dexamethasone, 2 factors implicated in beta cell maturation, increase PrP mRNA steady state level. PrP can thus be added to the list of neuronal factors expressed in the endocrine pancreas. Moreover, beta cells could represent a new model to study the control of PrP expression.