Abstract
Due to increased secretion and /or a reduced clearance rate plasma concentrations of endothelin-1 are, in a variety of pathological conditions, in the same range as those induced by the peptide's exogenous administration. While the currently available evidence nicely demonstrates that endothelins exert pharmacologic effects in virtually every endocrine system studied so far it is, at this point, difficult to assess the physiological and pathophysiological relevance of these observations. The advent of clinically applicable endothelin-antagonists hopefully will provide a new tool to approach this yet unsolved question.