Nitroxyl (HNO) acutely activates the glucose uptake activity of GLUT1

Nitroxyl (HNO) is a molecule of significant interest due to its unique pharmacological properties, particularly within the cardiovascular system. A large portion of HNO biological effects can be attributed to its reactivity with protein thiols, where it can generate disulfide bonds. Evidence from studies in erythrocytes suggests that the activity of GLUT1 is enhanced by the formation of an internal disulfide bond. However, there are no reports that document the effects of HNO on glucose uptake. Therefore, we examined the acute effects of Angeli's salt (AS), a HNO donor, on glucose uptake activity of GLUT1 in L929 fibroblast cells. We report that AS stimulates glucose uptake with a maximum effective concentration of 5.0 mM. An initial 7.2-fold increase occurs within 2 min, which decreases and plateaus to a 4.0-fold activation after 10 min. About 60% of the 4.0-fold activation recovers within 10 min, and 40% remains after an hour. The activation is blocked by the pretreatment of cells with thiol-reactive compounds, iodoacetamide (0.75 mM), cinnamaldehyde (2.0 mM), and phenylarsine oxide (10 μM). The effects of AS are not additive to the stimulatory effects of other acute activators of glucose uptake in L929 cells, such as azide (5 mM), berberine (50 μM), or glucose deprivation. These data suggest that GLUT1 is acutely activated in L929 cells by the formation of a disulfide bond, likely within GLUT1 itself.