STRESS DECREASES THE SERUM LEVEL OF OSTEOCALCIN

During a study undertaken to characterize the time course of the osteo calcin response to bone fractures, lower than normal values of serum o steocalcin (1.7 +/- 0.9 vs. 3.3 +/- 1.3 ng/ml, P < 0.001) were found i n the basal samples (blood obtained 48-72 h after fracturing). Suspect ing that such a decrease could be due to the stress response induced b y the fracture, for corticosteroids are known to diminish serum osteoc alcin, we extended our study to another two stressful situations of hi gh stress: acute myocardial infarction and elective abdominal surgery. Indeed, the concentration of osteocalcin was also significantly dimin ished in both of these (2.0 +/- 0.9 ng/ml, P < 0.0005; 1.5 +/- 1.0 ng/ ml, P < 0.0001). To further characterize this phenomenon, the time cou rse of osteocalcin changes during the 24 h following abdominal surgery was studied in a second group of patients. The decrease was found to begin soon after surgery. In order to exclude the immobilization prese nt in those three situations as the cause of the decrease in serum ost eocalcin, a group of patients with retinal detachment was studied. The ir serum osteocalcin levels were normal. It is concluded that serum os teocalcin levels decrease in stressful situations. Therefore, they sho uld be interpreted cautiously when used as a marker of osteoblastic ac tivity in this setting.