The Insulin-Mimetic Agent Vanadate Promotes Receptor Endocytosis and Inhibits Intracellular Ligand-Receptor Degradation by a Mechanism Distinct From the Lysosomotropic Agents

Vanadate (sodium orthovanadate) is an insulin-mimetic agent and phosphotyrosine phosphatase inhibitor that has been proposed as a potential therapeutic agent for diabetes. We previously reported that vanadate decreased the number of cell-surface insulin receptors but inhibited receptor degradation in cultured lymphocytes (IM-9) (1). To determine whether vanadate affected receptors without intrinsic tyrosine kinase activity, its effects on LDL …