[Effect of thyroid hormones on calcitonin secretion].

A study of 140 patients with diffuse toxic goiter showed phasic change in plasma calcitonin concentration and blood calcitonin activity: an increase in these indices at early stages of disease with a subsequent decrease in a severe form of thyrotoxicosis. Basal calcitonin secretion by fragments of the thyrotoxic thyroid was much higher than that euthyroid gland. In incubation of paranodal tissue of the thyroid of patients with nodular euthyroid goiter and fragments of the thyroid of patients with thyrotoxicosis of moderate severity with thyroxin at concentration 10(-8) M the level of calcitonin secretion considerably increased, concentration 10(-6) M was ineffective. The thyroid taken peroperatively from patients with diffuse toxic goiter with thyrotoxicosis of a severe form turned out nonreactive with relation to thyroxin concentration 10(-8) M. Basal calcitonin secretion in the study group was within control values. Thyroxin showed the properties of a calcitonin-secretion stimulator. Signs of depletion of the thyroid calcitonin-producing capacity were revealed in the course of development of diffuse toxic goiter.