Endothelin immunoreactivity in mice with gram-negative bacteraemia: relationship to tumour necrosis factor-alpha.
 1.
 To investigate the role of endothelin in Gram-negative bacteraemia and the possible involvement of tumour necrosis factor-alpha in its pathophysiology, we measured plasma and tissue (lung, kidney and spleen) immunoreactive endothelin levels in Gram-negative bacteraemic mice, with and without passive immunization by anti-(tumour necrosis factor-alpha) antibody.
 2.
 Plasma immunoreactive endothelin levels were greatly increased after the Escherichia coli injection.
 Pretreatment with anti-(tumour necrosis factor-alpha) antibody did not suppress elevated plasma immunoreactive endothelin levels (P greater than 0.1).
 3.
 Lung tissue immunoreactive endothelin levels in mice were increased 16 h after the E.
 coli injection and were not affected by prior passive immunization with anti-(tumour necrosis factor-alpha) antibody.
 Immunoreactive endothelin in spleen and kidney was undetectable (less than 34 fmol/g wet weight).
 4.
 Injection of rMu tumour necrosis factor-alpha into mice did not increase plasma immunoreactive endothelin levels.
 5.
 Antibody to endothelin given 30 min after a 90% lethal dose challenge with E.
 coli did not affect mortality.
 6.
 We conclude that the rise in plasma and tissue endothelin that occurs in Gram-negative bacteraemia is independent of tumour necrosis factor-alpha.
