Fig. 1

Low Ca stimulates PTH and 1,25(OH)₂D₃ expression. a Serum Ca in the denosumab alone group did not show any significant changes, but was decreased at 1 week and 1 month followed by a return to baseline levels at 4 months. In the BP pre-treated group, Ca was increased at 1 week and 1 month and gradually decreased thereafter. Group comparisons showed no significant differences at any time point. Straight line: Pre-treated BP group, dotted line: Denosumab alone group. b In the denosumab alone group, serum 1,25(OH)₂D₃ was significantly increased from 1 week to 2 months, and then gradually decreased thereafter. In the BP pre-treated group, serum 1,25(OH)₂D₃ did not significantly change during the study period. Group comparisons showed significant differences from 1 week to 4 months. Straight line: Pre-treated BP group, dotted line: Denosumab alone group. Asterisks indicate significant differences. c In the denosumab alone group, whole PTH was significantly increased at 1 week, and then gradually decreased thereafter. In the BP pre-treated group, PTH did not significantly change during the study period. Group comparisons showed significant differences at 1 week and 1 month. Straight line: Pre-treated BP group, dotted line: Denosumab alone group. Asterisks indicate significant differences