Calcitonin activity assessed by calcium tolerance test in patients with thyroid disorders.

The calcium tolerance test was performed in 34 healthy subjects and in 103 patients with simple goitre, thyrotoxicosis, hypothyroidism, subacute thyroiditis, medullary carcinoma and in patients after subtotal or total thyroidectomy and after radioiodine therapy. Calcium lowering activity which reflects mainly the activity of clacitonin, was significantly impaired in thyrotoxic and totally thyroidectomized patients. An abnormal calcium tolerance test in a patient with medullary carcinoma corresponded with large amounts of released calcitonin.