Differentiation-inducing factor of D. discoideum raises intracellular calcium concentration and suppresses cell growth in rat pancreatic AR42J cells.

DIF (differentiation-inducing factor) is a putative morphogen that induces stalk cell differentiation in the lower eukaryote, Dictyostelium discoideum. In this study, we have examined the effects of DIF on growth and the intracellular calcium concentration ([Ca2+]i) in rat pancreatic acinar AR42J cells. Growth of AR42J cells was inhibited when DIF was present in the media, and approximately 50% growth inhibition was attained with 20 microM DIF. DIF was also found to raise [Ca2+]i in a dose-dependent manner (1-40 microM), both in the presence and absence of extracellular Ca2+. These results suggest that DIF elicits both calcium influx from the extracellular space and calcium release from intracellular pool(s), thereby inhibiting cell growth in AR42J.