Oral insulin-mimetic compounds that act independently of insulin

Effect of vanadate on gene expression of the insulin signaling pathway in skeletal muscle of streptozotocin-induced diabetic rats

An insulin signaling pathway microarray was used to evaluate the gene expression profiling of the insulin signaling pathway in the skeletal muscle of streptozotocin-induced diabetic, NaVO(3)-treated diabetic and insulin-treated diabetic rats for the investigation of the effect of vanadium and insulin on the insulin signaling pathway. Of 96 genes surveyed, transcriptional patterns of 19 genes (20%) showed alterations in diabetic rats compared with controls. Although most of these changed gene expressions were improved after treatment with NaVO(3) (14, 74%) and insulin (16, 84%), NaVO(3) and insulin treatment resulted in the alteration of 20 and 12 additional gene transcripts compared no treatment. We found that both NaVO(3) and insulin treatment achieved a desirable glucose level and most of the alterative gene transcripts in diabetic rats were normalized with NaVO(3) and insulin treatment. Comparison of the gene expression profiling indicates that there is a significant difference between the NaVO(3)-treated group and the insulin-treated group. The present study demonstrated for the first time that several candidate genes of the insulin signaling pathway are involved in the effect of vanadium treatment on hyperglycemia. This study opens the way for more focused investigations that may identify the genes responsible for diabetes and vanadium treatment in the global insulin signaling pathway.

Understanding the mechanism of action of the novel SSAO substrate (C7NH10)6(V10O28).2H2O, a prodrug of peroxovanadate insulin mimetics

A new vanadium salt, hexakis(benzylammonium) decavanadate (V) dihydrate (C(7)NH(10))(6)(V(10)O(28)).2H(2)O (1), has been synthesized as well as characterized chemically and biologically. An in vitro enzyme assay revealed that compound 1 is oxidized to the same extent as a combination of benzylamine and vanadate by the enzyme semicarbazide-sensitive amine oxidase (SSAO), and therefore can be considered an SSAO substrate. It also stimulates glucose uptake in isolated rat adipocytes in a dose-dependent manner. We describe here the results of (51)V-NMR experiments that, combined with the in vitro results, corroborate that compound 1 could act as a prodrug of di-peroxovanadate ([V(OH)(2)(OO)(2)(OH)(2)](2-)) insulin mimetics.