[Endothelin: the vasoconstrictor of the 1990's?].

Endothelin is a recently isolated 21 amino acid peptide with vasoconstrictor activity. It seems to be part of the "hormonal" production by the vascular endothelium and might play a key role in the regulation of vasomotricity. The principal property of endothelin is that it induces an intense and prolonged arterial and venous contraction. Endothelin is secreted by endothelial cells under the influence of various stimuli (thrombin, adrenaline, shearing stress, hypoxia, etc.), then binds to specific membrane receptors thereby increasing the intracellular free calcium concentration. Endothelin has many other vascular and extravascular properties: it has positive inotropic and chronotropic effects, increases renal vascular resistances and reduces the glomerular filtration rate, contracts bronchial and gastrointestinal smooth muscle, induces proliferation of the vascular smooth muscle cells as well as that of fibroblasts and glomerular mesangial cells. Compared with experimental data in animals, human data are still scantly. Plasma endothelin concentration rises in acute renal failure and in chronic renal failure treated by dialysis, diabetes mellitus, essential arterial hypertension, pre-eclampsia and asthma. The development of specific antagonists and endothelin in synthesis inhibitors should soon enable us to specify the modes of regulation of endothelin production before considering applications to therapy.