In the present study, the effect of
glucosamine administration (1.5 or 3 g/day) on cartilage and bone metabolism was investigated in bicycle racers, using cartilage‑ and bone‑specific
biomarkers, including C‑terminal cross‑linked telopeptides of type II
collagen (CTX‑II), C‑terminal propeptides of type II
procollagen (CPII), N‑terminal telopeptides of bone‑specific type I
collagen (NTx) and bone
alkaline phosphatase (BAP). The results indicate that CPII (a marker of type II
collagen synthesis) was not substantially changed, however, CTX‑II (a marker of type II degradation) was reduced by
glucosamine administration, particularly at a dose of 3 g/day. Consistent with these observations, the ratio of CTX‑II/CPII was reduced by
glucosamine administration and the effect of
glucosamine was dose‑dependent. By contrast, the levels of NTx (a
bone resorption marker) and BAP (a bone formation marker) were not altered by
glucosamine administration. A previous study by this group reported that
glucosamine exerts a chondroprotective action in soccer players by preventing type II
collagen degradation but maintaining type II
collagen synthesis. Together these observations indicate that
glucosamine may exert a chondroprotective action by preventing type II
collagen degradation in athletes of various sports, including soccer players and bicycle racers.