Mean (±SD) calcium-PTH dynamics in normal subjects and patients receiving lithium carbonate

The curves were generated by measurements of serum PTH 30 minutes after serum ionized calcium concentrations had been raised or lowered by administration of calcium or citrate, respectively. The serum calcium-PTH curve is shifted to the right in the lithium-treated patients, and the set point is 5.10 mg/dL (1.28 mmol/L), as compared with 4.86 mg/dL (1.22 mmol/L) in the normal subjects.