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FIGURE 1. Activity in blood and NIS-expressing tissues. Error bars represent 1 SD. Note the variable y-axis scales. Radiopharmaceutical uptake was similar for the 3 radiopharmaceutical substrates, with the exception of iodide in the thyroid. Blood activity gradually decreased with time and was noted to be slightly greater in mice administered perchlorate, as a result of absence of competing excretory pathways. Uptake in NIS-expressing stomach and salivary gland was relatively high, remained elevated or increased over the initial 2 h, and subsequently washed out. This pattern also characterized perrhenate and pertechnetate uptake in the thyroid. However, iodide continued to increase through the 19-h time point, presumably as a result of organification. Blocking of NIS by coinjection of perchlorate decreased uptake of all 3 radiopharmaceuticals by the stomach, salivary glands, and thyroid and resulted in their rapid clearance, paralleling clearance in blood.
