Peroperative studies of S-calcitonin in thyroid and peripheral venous samples from patients with normal C-cells, C-cell hyperplasia, and medullary carcinoma on the thyroid.

The calcitonin (Ct) secretion was studied during surgery in 11 patients with benign thyroid and/or parathyroid disorders and in six patients with familial medullary carcinoma of the thyroid (MCT) and C-cell hyperplasia (CCH). The preoperative diagnosis of MCT and CCH was established by S-Ct determinations before and after pentagastrin provocation. During surgery blood samples were collected from thyroid and peripheral veins before and after injection of 0.6 micrograms pentagastrin . kg-1 in the inferior thyroid artery. In the control group the thyroid venous concentration of S-Ct increased from 395 +/- 42 pmol . l-1 to 2,692 +/- pmol . l-1 after intra-arterial (i.a) pentagastrin. The basal value for S-Ct in thyroid venous samples from patients with MCT and CCH was distinctly elevated in five of six patients. After pentagastrin stimulation a very prompt and striking S-Ct peak in thyroid venous samples was demonstrated (range 11,500-2,700,000 pmol . l-1), which in all cases widely exceeded that in the control group. Varying responses were registered in peripheral vein samples. S-Ct values obtained in the present investigation constitute valuable information for the interpretation of S-Ct values obtained in thyroid venous catheterization studies.