摘要：AIM and METHODS: To investigate the effect of endotoxin on the celluar activity and secretion of endothelin-1 by radioimmunoassay and MTT methods in cultured human umbilical vein endothelial cells stimulated by E coli endotoxin (E coli O55:B5, Sigma) of various concentrations (1 g/L, 100 mg/L， 10 mg/L，1 mg/L，100 μg/L，10 μg/L, 1 μg/L) and at the same time interval (HUVEC stimulated by endotoxin for 6 hours) in vitro.RESULTS:Endotoxin showed a slightly inhibitory effect on the viability of endothelial cells at low doses (1 μg/L， 10 μg/L, 100 μg/L, 1 mg/L). The viabilities were 92.00%±1.45%， 91.81%±2.03%, 89.52%±1.49%, 88.35%±1.88%, respectively, versus control group, P＜0.01. The cells were impaired significantly at the higher dose of LPS (100 mg/L), the viability was 80.49%±8.76%, versus control group, P＜0.01. The cells were killed evidently at the concentration of LPS (1 g/L), the viability was 73%±8%, versus control group, P＜0.01. The secretion of ET-1 increased gradually with the concentration of endotoxin manifolding. The concentration of ET-1 reached its peak at the dose of 100 μg/L, and it was (324.384±17.023) ng/L, versus control group (251.636±17.023) ng/L, P＜0.01. Endotoxin was effective in stimulating the endothelial cells to secret ET-1 in a dose dependent manner. CONCLUSION: These findings suggested ET-1 may be one of the important factors in endotoxic shock, and the increase in plasma ET-1 level in endotoxemia may be associated with increase in ET-1 secretion.