Distribution of prolylhydroxyproline and its metabolites after oral administration in rats

Kawaguchi T, Nanbu PN, Kurokawa M · Biological and Pharmaceutical Bulletin

Radioactivity reached articular cartilage and was taken up by chondrocytes, synovial cells, osteoblasts and osteoclasts. Of the label recovered from cartilage, 56% was proline-modified peptides, 5% intact Pro-Hyp and 28% non-peptide metabolites — so a small fraction does arrive intact, and most does not.

Population

Rats given oral [14C]-labelled Pro-Hyp, whole-body autoradiography and tissue thin-layer chromatography

Intervention

Single oral dose of [14C]Pro-Hyp

Limitations

Rats, not humans; authored by an employee of Q'sai Co., a collagen supplement manufacturer; radiolabel tracks carbon, so only the chromatography distinguishes intact peptide from recycled label.