Insulin-like and non-insulin-like action of vanadate in hepatocytes cultured in vitro

The aim of this study was to determine possible insulin-mimetic effects of vanadate on amino acid transport, glycogen synthesis and glucose production in hepatocytes cultured in vitro. Vanadate, like insulin, caused a significant (100%) increase of amino acid transport. However, vanadate produced a significant (31%) decrease of 14C-glucose incorporation into glycogen, in contrast to insulin which caused a 54% increase. Vanadate also caused a significant decrease (24%) of basal glucose production but had no effect on glucagon-stimulated glucose production. Vanadate and insulin given together reduced more strongly the basal glucose production (68%) and also effectively prevented the glucagon-stimulated effect on glucose production. In hepatocytes cultured in vitro vanadate had insulin-like and non-insulin-like action. Our results clearly demonstrated that non-insulin-like effects of vanadate could have a beneficial influence on the therapy of diabetes type 2 causing a decrease of glucose production from the liver.