Endothelin-1 is 21-amino acid peptide that potentially modulate renal function. EI-1 produced by and binds to most renal cell types. EI-1 exerts a wide range of biologic effects in kidney. EI-1 levels were found to be elevated in patients with a acute rejection and the mitogenic and pressor actions of EI-1 must contributes to transplant vasculopathy.