Effect of sodium azide on the metabolic activity of cultured fetal cells.

Sodium azide is a highly toxic substance. However, the mechanism of its toxicity has not been fully established. In the present study, we attempted to investigate the toxicity of sodium azide in various cultured fetal cells, using changes in cellular respiration as an indicator of metabolic inhibition to elucidate tissue-specificity. The human fetal cell lines used in this study included myocardial cells, nerve cells, fibroblasts, hepatocytes and renal tubular epithelial cells. The cells were seeded in wells at a density of 2 x 10(6)cells/2mL, sodium azide was added at a concentration of 0.01 ng/mL to 10 microg/mL, and the respiration of each type of cell was measured 1 h later using a dissolved oxygen meter. The concentration at which sodium azide inhibited metabolic activity was lower in the nerve and myocardial cells than in the fibroblasts, hepatocytes and renal tubular epithelial cells. These findings may serve to clarify the dynamic mechanisms of sodium azide toxicity in vivo.