Distinct actions of prednisolone and dexamethasone towards osteocalcin and eosinophilic cationic protein in assumed clinically equivalent doses: a study in healthy men

Objective: To study the effects of prednisolone (PRED) and dexamethasone (DEXA) in assumed clinically equivalent doses towards the lowering of cortisol, osteocalcin (OC) and the stimulated rise of eosinophilic cationic protein (ECP) by granulocyte colony stimulating factor (G-CSF). Methods: At four separate sessions of 25 h each, saline i.v. alone, G-CSF s.c. alone or in combination with either 12.5 mg PRED i.v. or 2.0 mg DEXA i.v., were randomly administered in eight healthy male subjects. Results: All subjects had equal lowering of cortisol after DEXA and PRED at 10 h, whereas a sustained suppression at 25 h persisted only after administration of DEXA. Between 4 h and 10 h after administration of DEXA and PRED, the change in the area under the concentration-time curve ( AUC(4-10)) of OC became 24.4% and 2.3% lower, respectively (p < 0.0001). After 25 h, this effect persisted for DEXA. DeltaAUC(4-10) of the G-CSF-stimulated ECP response decreased by a mean of 76.8% after PRED compared with DEXA and to controls (p < 0.02), and this difference had disappeared at 25 h. DEXA did not elicit any effect towards the G-CSF-stimulated ECP response. Conclusion: PRED and DEXA in formerly assumed clinically equivalent doses induced a similar suppression towards cortisol within the first 10 h, but had different actions towards blood concentrations of OC and ECP following G-CSF stimulation in healthy male subjects.