An electrophoretic fraction of urinary glycosaminoglycans reflecting connective tissue turnover.

In 97 healthy individuals, including 64 children, the excretion of glycosaminoglycan-derived uronic acid, hydroxyproline and creatinine was determined. In 32 of the individuals the glycosaminoglycans were separated into two electrophoretic fractions. The excretion of both were expressed as uronic acid. One of these fractions correlated with the excretion of hydroxyproline producing a peak of excretion at puberty. Constituting up to 30% the other fraction was excreted independently of hydroxyproline and was rather constant throughout life. Regarded as a fraction without any relation to the ground substance of bone, cartilage, tendons and skin, the independent fraction represented a disturbing factor in the investigation of connective tissue by urinary measurements. Due to the correlation above, glycosaminoglycans and hydroxyproline showed identical sex-and age-dependent patterns of excretion. Peak excretions were found at puberty, and when expressed as ratios with creatinine, linear decreases during adolescence were the results. The uronic acid/hydroxproline ratio was constant throughout childhood, but increased a little in adults.