Endocrine Abstracts

Prednisolone has been reported to have greater deleterious effects on bone turnover than other glucocorticoids, although the evidence for this is confounded by the effects of higher dose prednisolone, as used in conditions such as asthma. We hypothesise that a physiological replacement dose of prednisolone will have a less dramatic effect on bone than has previously been suggested, and might be safer than hydrocortisone for replacement in adrenal insufficiency. We investigated the effect of low-dose prednisolone on bone turnover markers including carboxylated osteocalcin (Gla-OC), undercarboxylated osteocalcin (Glu-OC), procollagen type 1 N-terminal propeptides (P1NP) and N-terminal telopeptide of type 1 collagen (NTx). Participants were given an oral dose of prednisolone (0–15 mg) at 8 AM. Serum Gla-OC, Glu-OC, P1NP and urine NTx levels were measured immediately before and 24 h after the dose was taken. There was significant suppression in the Gla-OC concentrations taken immediately before the dose compared to 24 h after (P<0.01), with lower values 24 h after the prednisolone dose (median 10.6 ng/ml, interquartile range 10.1–11.2 ng/ml) compared to the baseline Gla-OC levels (median 12.7 ng/ml, interquartile range 10.7–12.9 ng/ml). There was also a significant suppression of Glu-OC concentrations with lower values 24 h after the prednisolone dose (median 3.6 ng/ml, interquartile range 3.5–3.8 ng/ml) compared to the baseline Glu-OC levels (median 4.3 ng/ml, interquartile range 4.1–4.5 ng/ml) (P<0.01). There was no significant change in NTx/creatinine ratios and P1NP concentrations after 24 h. This suggests that osteoblast production of osteocalcin is suppressed after glucocorticoid treatment. Gla-OC and Glu-OC are biomarkers that can be utilised to monitor patients’ acute response to prednisolone in a larger study.