Sodium tungstate mimics insulin effect on nuclear translocation of FBPase in rat liver

Abstract

Sodium tungstate (NaW) is an inorganic salt that has proven to be a potent insulin-mimetic agent, although the molecular events seems to differ. Inhibition of hepatic gluconeogenesis is one significant physiological action of insulin, therefore studying the effect of NaW on gluconeogenic enzymes will contribute to understand its elusive mechanism of action. Here, we show that NaW has no inhibitory effect over the gluconeogenic enzyme fructose 1,6-bisphosphatase (FBPase) in vitro, but mimics insulin in the induction of the nuclear translocation of FBPase in rat liver, which may have a negative impact on its activity. Then, at least in part, NaW may inhibit hepatic gluconeogenesis by inducing the proper subcellular distribution of FBPase, without directly interfering with its phosphatase activity.