Serum concentrations of keratan sulfate, osteocalcin, and pyridinoline crosslinks after oral administration of glucosamine to standardbred horses during race training.
OBJECTIVE
To determine the effects of orally administered glucosamine on concentrations of markers of bone and cartilage metabolism in Standardbred horses during race training.


METHODS
Twenty 16- to 20-month-old Standardbreds beginning race training.


METHODS
Horses were randomly assigned to 2 groups. One group received glucosamine hydrochloride (4 g, PO, q 12 h), and the second (control) group received glucose (4 g, PO, q 12 h). Serum samples were obtained prior to onset of the study (baseline) and at regular intervals for 48 weeks for determination of concentrations of keratan sulfate (KS), osteocalcin (OC), and pyridinoline crosslinks (PYD).


RESULTS
Osteocalcin concentrations changed significantly with time; mean serum concentrations were significantly higher than baseline values for samples obtained at 24 to 48 weeks after onset of the study. Although a significant effect of time was observed for mean concentration of KS, concentrations did not differ significantly from baseline values at any time during the study when groups were analyzed separately. However, pooled analysis revealed significant increases of mean serum KS concentration at weeks 24 and 30. Significant changes in serum PYD concentrations were not detected. Oral administration of glucosamine did not significantly affect serum concentrations of any of the markers.


CONCLUSIONS
Increased serum OC in clinically normal Standardbreds during race training may reflect bone formation that accompanies adaptive remodeling of the appendicular skeleton. For these experimental conditions, glucosamine did not appear to exert a detectable influence on serum concentrations of these 3 markers of connective tissue metabolism.
Caron
John P
JP
Departments of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1314, USA.
Peters
Tonia L
TL
Hauptman
Joseph G
JG
Eberhart
Susan W
SW
Orth
Michael W
MW
D000284:Administration, Oral; D000596:Amino Acids / Q000097:blood*; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism; D002356:Cartilage / Q000378:metabolism; D003094:Collagen / Q000097:blood; D005944:Glucosamine / Q000494:pharmacology*; D006736:Horses / Q000097:blood* / Q000378:metabolism / Q000502:physiology; D007632:Keratan Sulfate / Q000097:blood*; D015675:Osteocalcin / Q000097:blood*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation
D000596:Amino Acids; D015675:Osteocalcin; C015484:pyridinoline; D003094:Collagen; D007632:Keratan Sulfate; D005944:Glucosamine