Abstract: A bradykinin analog which contains nine or ten amino acid residues and at least one [CH.sub.2 NH] pseudopeptide bond, the analog being useful as an antagonist or agonist of the naturally occuring bradykinin.

Abstract: A method of determining collagen degradation in vivo, including quantitating the concentration of a peptide in a body fluid, the peptide being a C-terminal type II collagen telopeptide containing a hydroxylysyl pyridinoline cross-link or a type III collagen telopeptide containing a hydroxylysyl pyridinoline cross-link. The method includes immunometric assays, fluorometric assays, and electrochemical titrations for quantitation. The structures of specific peptides having cross-links and kits for quantitating these peptides in a body fluid are described.