CALCIUM INFUSION AND PENTAGASTRIN INJECTION IN DIAGNOSIS OF MEDULLARY-THYROID CARCINOMA

  • 1 January 1978
    • journal article
    • research article
    • Vol. 119  (1) , 29-+
Abstract
Ca infusion and pentagastrin injection were compared as tests to stimulate calcitonin secretion for the detection of medullary carcinoma of the thyroid. Plasma concentrations of immunoreactive calcitonin were measured by radioimmunoassay before and during both stimulation tests in 2 persons who had been found at operation to have medullary thyroid carcinoma, 1 relative in whom a cervical lymph node biopsy had shown medullary thyroid carcinoma and 36 asymptomatic relatives. The tests were carried out on separate days by i.v. infusion of calcium gluconate for 2 h, to provide 3.75 mg/kg of elemental Ca/h and rapid i.v. injection of 0.5 .mu.g/kg of pentagastrin. Before stimulation immunoreactive calcitonin was undetectable in the plasma of 34 of the 36 asymptomatic persons; the 2 with elevated baseline concentrations of the hormone had a positive response to both tests. Seven others showed an increase in plasma immunoreactive calcitonin concentration only after pentagastrin injection. The 2 persons with initially elevated values and 3 of the 7 with increased values after pentagastrin injection were found at subsequent operation to have focal medullary carcinoma and parafollicular cell hyperplasia; after the operation immunoreactive calcitonin was undetectable in the plasma, even after stimulation. Rapid injection of pentagastrin is more reliable than slow infusion of Ca as a stimulation test for the early detection of medullary thyroid carcinoma.