Introduction: Bone and energy metabolisms are deeply related determining a two-way street aimed in regulating the energy utilization . Mountain ultra-marathons are peculiar aerobic performances hardly proving whole body homeostasis . In this study we aimed at investigating and characterizing the metabolic profile (hormones involved in energy metabolism), the metabolic inflammation profile (adipokines), the bone metabolism (bone turnover markers), and their integration (mediated by osteocalcin ) both in experienced ultra-marathon runners and control subjects.
Methods: Serum concentrations of bone turnover markers (pro-collagen type I N-terminal propeptide, carboxylated/undercarboxylated osteocalcin), measured by ELISA, and metabolic hormones (C-peptide, insulin, glucagon, glucagon-like peptide, gastric-inhibitory peptide, ghrelin, leptin, resistin, and visfatin), measured by fluorescent-based multiplex assay, were compared before and after a 65-km mountain ultra-marathon in 17 trained runners and in 12 age-matched controls with a low physical activity profile.
Results: After the race, runners experienced a reduction in pro-collagen type I N-terminal propeptide (P< 0.05), although it remained higher than in controls (P< 0.05), while carboxylated osteocalcin remained unchanged. Among the metabolic hormones, only glucagon and leptin were different between runners at rest and controls. C-peptide and leptin decreased after the race in runners, while glucagon, glucagon-like peptide 1, resistin, and visfatin were increased (P< 0.01). Undercarboxylated osteocalcin was decreased (50%, P< 0.05) and highly correlated with insulin and C-peptide (r=0.65, P< 0.01).
Conclusions: In order to keep homeostasis, the energy use is strikingly regulated at expenses of bone metabolism. Undercarboxylated osteocalcin changes clearly mark the global energy needs of the body.