The Insulin-Mimetic Effect of Vanadate Is Not Correlated with Insulin Receptor Tyrosine Kinase Activity Nor Phosphorylation in Mouse Diaphragmin Vivo

The in vivo administration of sodium orthovanadate stimulated the incorporation of [14C]glucose into [14C] glycogen, in a dose- and time-dependent manner, in mouse diaphragm. Activation of diaphragm insulin receptor was measured by exogenous tyrosine kinase activity and an antibody that recognizes a conformational change in the receptor beta-subunit upon autophosphorylation. Neither method detected insulin receptor activation by in vivo vanadate administration, suggesting that vanadate's insulin-mimetic effect on mouse diaphragm glycogenesis occurs at a site distal to the insulin receptor.