This invention relates to muteins of amylin and derivatives thereof having insulin action suppressing activity as well as the pharmaceutically-acceptable salts thereof. The muteins and derivatives of this invention are useful for suppressing insulin action in muscle or muscle cells and for suppressing insulin action in a mammal in need thereof. Thus, this invention further relates to a method of suppressing insulin action in a mammal in need thereof and methods for suppressing insulin action in muscle or muscle cells as well as pharmaceutical compositions comprising the above described muteins, derivatives or salts. This invention also relates to a method for assaying the ability of a compound to inhibit the suppression of insulin action in muscle or muscle cells caused by amylin.
