Stimulation of glucose transport by semicarbazide-sensitive amine oxidase activity in adipocytes from diabetic rats.

Semicarbazide-sensitive amine oxidase (SSAO) is highly expressed in adipose cells, and substrates of SSAO such as benzylamine in combination with low concentrations of vanadate strongly stimulate glucose transport and GLUT4 recruitment in mouse 3T3-L1 adipocytes and in isolated rat adipocytes. Here we examined whether this combination of molecules also stimulates glucose transport in adipocytes from streptozotocin-induced diabetic rats and from Goto-Kakizaki diabetic rats. As previously reported, adipocytes obtained from streptozotocin-induced diabetic rats, showed a reduced stimulation of glucose transport in response to insulin. Under these conditions, the combination of benzylamine and vanadate caused a marked stimulation of glucose transport that was similar to the stimulation detected in control adipocytes. Adipocytes isolated from Goto-Kakizaki diabetic rats also showed a defective response to insulin; however, acute incubation in the presence of benzylamine and vanadate stimulated glucose transport in these cells to the same extent than in adipocytes from non-diabetic rats. These data indicate that adipocytes obtained from two different models of animal diabetes do not show resistance to the activation of glucose transport by SSAO activity, which is in contrast to the well reported resistance to insulin action. It seems to suggest that SSAO activity in combination with vanadate triggers a glucose transport-activating intracellular pathway that remains intact in the diabetic state. Further, our data support the view that the combination of benzylamine and vanadate could be an effective therapy in diabetes.