Elevated Intact Parathyroid Hormone Is Associated with Reduced Biochemical Markers of Bone Formation and Resorption Measured in Blood in Infant Piglets Receiving Oral Dexamethasone for 15 Days

Seven-day-old male Yorkshire piglets were randomized to receive either dexamethasone (DEX) 0.5 mg/kg/day or placebo (water) for 15 days (n = 8/group). Body weight and length, plasma intact parathyroid hormone (PTH), N-Mid osteocalcin and C-terminal telopeptide of type I collagen (CTx) were measured at baseline and end of the study. The indices of bone metabolism did not differ between DEX and placebo groups at baseline. At the end of the study, plasma intact PTH was increased (p < 0.01) and N-Mid osteocalcin (p < 0.01) and CTx (p < 0.01) were decreased from baseline value in the DEX group but not in the placebo group. The reduction (Z-score) in N-Mid osteocalcin was greater than that in CTx (p < 0.05). We conclude that exogenous DEX in young piglets stimulates a rise in circulating intact PTH. Both circulating CTx and osteocalcin are reduced with the decline in osteocalcin greater than that in CTx.