Collagen-like fragments: excretion in urine of patients with Paget's disease of bone

Patients with Paget's disease of bone excrete, in the urine, polypeptides that have amino acid composition and other properties resembling those of fragments of collagen. The pattern of isotope incorporation in vivo suggests that these fragments are derived from collagen that has been synthesized and rapidly degraded, or that they are rapidly synthesized but not incorporated into tropocollagen molecules.