Relations of Calcitonin and Gastrin in the Zollinger-Ellison Syndrome and Medullary Carcinoma of the Thyroid

Fasting plasma immunoreactive human calcitonin and fasting serum immunoreactive human gastrin were measured by specific radioimmunoassays in 16 healthy persons, eight patients with the Zollinger-Ellison syndrome who had no clinical thyroid disease, and seven patients with medullary carcinoma of the thyroid. All patients with the Zollinger-Ellison syndrome had high serum immunoreactive gastrin (p < 0.01), and all with thyroid carcinoma had high plasma immunoreactive calcitonin (p < 0.025). Mean plasma immunoreactive calcitonin was increased significantly in patients with the Zollinger-Ellison syndrome (p<0.005). Mean serum immunoreactive gastrin was decreased significantly in the patients with carcinoma(p < 0.01). One patient with the Zollinger-Ellison syndrome and high plasma immunoreactive calcitonin had no post-mortem histologic evidence of medullary carcinoma of the thyroid. These observations suggest a possible interhormonal relation between calcitonin and gastrin in man, calcitonin inhibiting gastrin secretion and, conversely, gastrin stimulating calcitonin secretion.