Enzymatic determination of urinary chondroitin sulphate: applications in renal stone disease and acromegaly

Abstract

A method was developed for the determination of urinary chondroitin sulphate (CS), including dermatan sulphate and chondroitin 4 and 6-sulphates, using an enzymatic degradation with chondroitinase-ABC followed by precipitation with Alcian blue, whereby CS was determined as the difference between undigested and chondroitinase digested material. The method was linear in the range 0-100 mg l-1 with a detection limit of 1 mg l-1 and allowed determinations on small urine volumes without pretreatment of the urine. It could be demonstrated that males excreted more CS than females, and growing children had the highest urinary content of CS. Renal calcium stone formers did not differ from healthy controls in urinary CS. Patients with acromegaly had a higher excretion of CS compared with controls. There was also, in these patients, a positive correlation between the serum growth hormone levels and the urinary CS, indicating that CS-excretion may be an estimate of the activity of the pituitary disorder.