US EPA

49957 

Journal Article 

Influence of pre- and simultaneous perfusion of ascending concentrations of lead on the effect of elevated calcium on digoxin-induced cardiac arrest in isolated frog heart 

Muthu, P; Krishnamoorthy, MS; Parthiban, N 

1993 

Yes 

Bulletin of Environmental Contamination and Toxicology
ISSN: 0007-4861
EISSN: 1432-0800 

50 

1 

77-84 

English 

8418941 

WOS:A1993JX84000013 

#To evaluate the toxicity of lead on the blood fibrinolytic system, vascular endothelial cells from human umbilical vein were cultured in the presence of lead and the content of tissue plasminogen activator antigen (t-PA:Ag) released into the medium was determined by enzyme immunoassay. It was found that lead significantly decreased the t-PA:Ag release from the cells. Although heavy metals including cadmium, mercury, cobalt, manganese, nickel, zinc and copper as well as lead each had an inhibitory effect, lead was the potent inhibitor. Lead significantly disturbed thrombin up-regulation of t-PA:Ag release and significantly amplified endothelin-1 down-regulation of it. Incorporation of [3H]thymidine into the acid-insoluble fraction of the cell layer was significantly increased by lead; however, that of [14C]leucine was unchanged by the metal. In lead-treated cells, a significant accumulation of lead was observed but calcium content was increased slightly. From these results, it was suggested that lead decreased the release of t-PA:Ag from cultured endothelial cells without nonspecific inhibition of protein synthesis; lead may stimulate the calcium-dependent down-regulation of endothelial cell t-PA:Ag release by calcium or by mimicking calcium.