The effect of treatment with PTH on undercarboxylated osteocalcin and energy metabolism in hypoparathyroidism

Abstract

Context: Undercarboxylated osteocalcin (ucOC) has been shown to affect glucose metabolism in mice.Werecently randomized patients with hypoparathyroidism to treatment withPTHor placebo and demonstrated a marked increase in total osteocalcin. Objective: To investigate whether there was a similar increase in ucOC and whether that increase affected glucose metabolism. Design: A 24-week randomized, placebo-controlled trial. Setting: Ambulatory patients in a research facility. Patients: Sixty-two patients aged 31-78 years with hypoparathyroidism, of which 58 completed the trial. Intervention: 100 μg/d of PTH (1- 84). Main Outcome Measure: Change in ucOC. Results: ucOC increased by 1185.0±814.4% (mean = SD) in the PTH-treated group and by 69.3±79.4% in the placebo group (P<10-50). In addition, body weight decreased by 1.1±4.0% in the treatment group and increased 0.8±2.5% in the placebo group (P=.04). Glucose, adiponectin, leptin, homeostasis model of assessment for insulin resistance, total body fat mass, or truncal fat did not change significantly. In addition, the number of hypercalcemic episodes per patient was 3.7±2.9 (mean=SD) in the PTH-treated group but only 0.2±0.6 in the placebo group (P<001). Moreover, there was a significant and negative correlation between the change in ucOC and change in body weight (P=.004) or change in total body fat mass (P=.03), and a negative but nonsignificant correlation between the number of hypercalcemic episodes and percentage change in body weight (r=-0.32; P=.1). Change in ucOC did not significantly correlate with changes in other parameters. Conclusions: An explanation for the weight loss may be subtle hypercalcemia in PTH treatment inhibiting appetite.Ourdatadonot support a role forucOCin energy metabolism in humans.