Metabolic alterations in dogs with osteosarcoma

Objective-To evaluate changes in resting energy expenditure (BEE) as well a s protein and carbohydrate metabolism in dogs with osteosarcoma (OSA). Animals-15 weight-stable dogs with OSA that did not have other concurrent m etabolic or endocrine illness and twelve 1-year-old sexually intact female Beagles (control dogs). Procedures-indirect calorimetry was performed on all dogs to determine BEE and respiratory quotient (RQ. Stable isotope tracers (N-15-glycine, 4.5 mg/ kg of body weight, IV; 6,6-deuterium-glucose, 4.5 mg/kg, IV as a bolus, fol lowed by continuous-rate infusion at 1.5 mg/kg/h for 3 hours) were used to determine rate of protein synthesis and glucose flux in all dogs. Dual-ener gy x-ray absorptiometry (DEXA) scans were performed to determine total body composition. Results-Accounting for metabolic body size, BEE in dogs with OSA was signif icantly higher before and after surgery, compared with BEE of healthy contr ol dogs. The RQ values did not differ significantly between groups. Dogs wi th OSA also had decreased rates of protein synthesis, increased urinary nit rogen loss, and increased glucose flux during the postoperative period. Conclusions and Clinical Relevance-Alterations in energy expenditure, prote in synthesis, urinary nitrogen loss, and carbohydrate flux were evident in dogs with OSA, similar to results documented in humans with neoplasia. Chan ges were documented in BEE as well as protein and carbohydrate metabolism i n dogs with OSA. These changes were evident even in dogs that did not have clinical signs of cachexia.