SERUM MARKERS OF BONE METABOLISM IN DOGS

Objective-To establish reference values for a panel of serum markers o f bone turnover in dogs of various ages. Animals-Dogs in 4 age groups (0 to 1 year; 1 to 2 years; 3 to 7 years; > 8 years). Procedure-Serum concentrations of the carboxyterminal propeptide of type-I procollagen (PICP) and the aminoterminal propeptide of type-I procollagen (PINP), both markers of type-I collagen synthesis thence, bone formation), we re measured by use of commercial human radioimmunoassay kits. Serum co ncentrations of the carboxyterminal cross-linked telopeptide of type-I collagen (ICTP), a marker for type-collagen breakdown (hence, bone re sorption), also were measured by use of a commercial human radioimmuno assay kit. Serum osteocalcin (OC) concentrations and alkaline phosphat ase (ALP) isoenzyme activities were measured by use of techniques deve loped specifically for dogs. Results-As expected, the highest values f or all of the markers were found in young dogs (< 12 months old). Conc entrations of OC and ICTP decreased with age, and were lowest in dogs > 8 years old. Total ALP and bone-specific ALP activities initially de creased with age, then increased in dogs > 8 years old. Conclusions an d Clinical Relevance-Serum markers of bone turnover may be useful diag nostic and prognostic tools for management of dogs with musculoskeleta l disorders.