Abstract: N-(5-isoxazolyl)benzenesulfonamides and N-(3-isoxazolyl)benzenesulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, N-(5-isoxazolyl)biphenylsulfonamides and N-(3-isoxazolyl)biphenylsulfonamides and methods for inhibiting the binding of an endothelin peptide to an endothelin receptor or increasing the activity of endothelin peptides by contacting the receptor with a sulfonamide are provided. N-isoxzolyl-4-biphenylsulfonamides are particularly preferred. These compounds exhibit activity as endothelin receptor B antagonists. Methods for treating endothelin-mediated disorders, particularly inflammatory diseases, such as asthma, by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.