EFFECTS OF SHORT-TERM TREATMENT WITH PREDNISOLONE AND CALCITRIOL ON BONE AND MINERAL METABOLISM IN NORMAL MEN

To study the effects of treatment with glucocorticoid and calcitriol o n biochemical markers of calcium and bone metabolism, 48 normal male v olunteers (aged 21-54 years) were randomized to treatment for 7 days w ith either (A) prednisolone, 10 mg twice daily, (B) prednisolone, 10 m g twice daily, and calcitriol, 1 mu g twice daily, (C) calcitriol 1 mg twice daily, or (D) placebo. The study period was 28 days. Renal calc ium excretion increased (mean maximal increase +44.7%, p < 0.01) as we ll as serum parathyroid hormone (PTH) (mas. +18.5%, p < 0.01) during p rednisolone treatment. Concomitant treatment with calcitriol or calcit riol alone equally enhanced renal calcium excretion (max. +185.2%, p < 0.001) and decreased serum PTH (max. -43.1%, p < 0.001). Prednisolone administration was followed by prompt declines in markers of bone for mation [serum osteocalcin (max. -34.7%, p < 0.001) and serum procollag en type I C-terminal propeptide (PICP) (max. -25.9%, p < 0.05)], where as serum bone alkaline phosphatase (bone AP) remained unchanged, Calci triol in combination with prednisolone attenuated the decrease in PICP (max. -8.9%, not significant), but it had no effect on osteocalcin (m as, -40.1%, p < 0.001), and decreased bone AP (max. -22.2%, p < 0.05). Calcitriol alone increased osteocalcin (max. +37.8%, p < 0.03) and PI CP (max. +26.0%, p < 0.05). Among markers of bone degradation, prednis olone suppressed serum C-terminal telopeptide of type I collagen (ICTP ) (max. -28.4%, p < 0.001), but not the fasting renal excretion of hyd roxyproline (OHP) and collagen type I N-terminal telopeptide (NTx). Ca lcitriol partially antagonized the decrease in ICTP (max. -17.20%, p < 0.001). Calcitriol alone had no effect on resorptive markers, Extraos seous matrix synthesis was suppressed by prednisolone evaluated by ser um procollagen type III N-terminal propeptide (max. -30.8%, p < 0.001) and was not affected by concomitant treatment with calcitriol or calc itriol alone. In conclusion, short-term administration of prednisolone to healthy men leads to Fast and protracted suppression of biochemica l markers of bone formation and extraosseous connective tissue metabol ism, The effect on bone was partially antagonized by simultaneous calc itriol treatment, and points toward a potential role of calcitriol in the prevention of steroid induced osteoporosis. (Bone 23:297-302; 1998 ) (C) 1998 by Elsevier Science Inc. All rights reserved.