Inhibition of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) endocytosis by ouabain in human endothelial cells.

3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) uptake and reduction is widely used to evaluate cell proliferation and viability. MTT is taken up by the cells through endocytosis. We find that ouabain (1-200 nM) inhibits MTT reduction in human umbilical vein endothelial cells (HUVEC) without affecting cell viability.