High bromide intake affects the accumulation of iodide in the rat thyroid and skin.

The effect of a high bromide intake on the kinetics of iodide uptake and elimination in the thyroid and skin of adult male rats was studied. In rats fed a diet with sufficient iodine supply (> 25 microg I/d), the iodide accumulation in the skin predominated during the first hours after 131I iodide application. From this organ, radioiodide was gradually transferred into the thyroid. A high bromide intake (> 150 mg Br-/d) in these animals led to a marked decrease in iodide accumulation, especially by the thyroid, because of an increase in iodide elimination both from the thyroid and from the skin. In rats kept under the conditions of iodine deficiency (< 1 micro I/d), the iodide accumulation in the thyroid, but not in the skin, was markedly increased as a result of a thyrotropic stimulation. The effect of a high bromide intake (> 100 mg Br-/d) in these animals was particularly pronounced because the rates of iodide elimination were most accelerated both from their thyroid and from their skin.