Effect of aminotriazole on thyroid function in the rat

Abstract

These studies were designed to determine the minimal dietary dose of aminotriazole (ATZ) producing a measurable effect on activity of the thyroid gland of male rats. At 0.5 ppm in food, no effect was observed on any of 7 separate measures of thyroid function studied. However, at 2 ppm in food, 2 of 16 separate measures of thyroid function were affected significantly. At 10 ppm in food, 3 of 16 measures were affected significantly while at 50 ppm, 5 of 16 measures were affected significantly. Hence, the dose of ATZ affecting activity of the thyroid gland lies somewhere between 0.50 and 2 ppm. ATZ acts on the thyroid gland by inhibiting uptake of radioactive iodide. Interrelationships among the various measures of thyroid activity were also studied by means of a correlation matrix. The measure correlating best with the others was uptake of 131I by the thyroid gland excised 24 hours after administration of the isotope.