Serum hydroxyproline and hydroxylysine levels in viral hepatitis.

High serum levels of total hydroxyproline (Hyp) and hydroxylysine (Hyl) in patients with acute viral hepatitis were found to be due to a marked increase of the peptide-bound form of these aminoacids. The concentrations of free Hyp and Hyl were only slightly changed. The levels of serum Hyp and Hyl were higher in patients with bilirubin concentration, and decreased during recovery.