Normal Blood Calcium Homeostasis in Response to Calcium Infusion in Pseudohypoparathyroidism and Idiopathic Hypoparathyroidism

Summary Blood calcium homeostasis after calcium infusion was measured in 4 pseudohypoparathyroid patients and in one patient with “idiopathic hypoparathyroidism”—as a reflection of possible excessive thyrocalcitonin secretion. The response was similar to that of normal subjects, and in no patient did the postinfusion level fall below the initial level. This is evidence against the concept that excessive thyrocalcitonin secretion produces the hypocalcemia in these diseases.