To the Editor.
—Vascular endothelial damage plays an important pathophysiological role in sepsis syndrome.1 During septicemia, bacterial endotoxin causes injury of vascular endothelial cells that produce and secrete several vasoactive substances. Recently, it has been reported that plasma levels of endothelin-1, a potent endothelium-derived vasoconstrictor peptide, are extremely elevated in patients with sepsis syndrome.2 Endothelin-3, on the other hand, is an isopeptide with less vasoconstrictive but more potent vasodilatory effect than endothelin-1, which also circulates in human plasma.3 To determine whether endothelin-3 is also of importance in the pathophysiology of sepsis syndrome, we measured plasma levels of immunoreactive endothelin-3 and endothelin-1 in patients with sepsis syndrome.We studied seven patients (four men and three women), 62 to 79 years of age, with sepsis syndrome. Their underlying diseases were postoperative infection (three), pneumonia (two), peritonitis (one), and pelvic abscess (one). Fifteen normal subjects (eight men and seven women)