A method of conditioning/improving lung functions extracorporeally by treatment of a lung ex vivo with a cyclized compound of the amino acid sequence of formula X1-GQRETPEGAEAKPWY-X2&emsp；&emsp；I wherein X1 comprises an amino acid (sequence) with 1 to 4 members, comprising natural or unnatural amino acids, and X2 comprises one amino acid, selected from natural amino acids； and a pharmaceutical composition, comprising a peptide of formula I as defined in any one of claims 1 to 7, in a form, which is appropriate for spraying to obtain an aerosol for inhalation, or which is appropriate for the preparation of a spray to obtain an aerosol upon spraying, which is appropriate for inhalation.
