Review Question - QID 108778

A 65-year-old female presents to her primary care physician for a routine check-up. She reports feeling well but has noticed occasional weakness and constipation over the past few months. A complete blood count is within normal limits. Serum calcium is 11.9 mg/dL and serum phosphate is 2.4 mg/dL. Urine calcium output is 400 mg/24 h. A sestamibi scan demonstrates increased uptake near the inferior left pole of the thyroid gland. Which of the following mechanisms is most likely involved in this patient’s symptoms?