The invention relates to a protein which is selected from the amino acid sequence of the region valine Val(91) to glycine Gly(121) of the mature, human tumor necrosis factor, or a part thereof, provided that the protein comprises at least the amino acid sequence of the region lysine Lys(98) to glutamic acid Glu(116), the cysteine Cys(101) being replaced by a glycine and an amide bond being formed between the amino group of the side chain of the lysine Lys(98) and the carboxyl group of the side chain of the glutamic acid Glu(116). The protein activates epithelial ion channels and improves the pulmonary function and can be used to produce drugs for the treatment of diseases that are associated with the pulmonary function, such as oedema.
