Effect of Short-term and Long-term Lithium Treatment on Uptake and Retention of 10dine-131 in Rat Thyroid

Abstract

No significant change occurred in the uptake by the thyroid of male Wistar rats of a standard dose of carrier-free 131 1 administered intraperitoneally and its retention by the thyroid, as measured by biological and effective half-life, after feeding these rats a powdered pelleted diet containing lithium carbonate (I .

Effect of lithium on thyroidal 131 iodine uptake, its clearance, and circulating levels of triiodothyronine and thyroxine in lead-treated rats

“…In this study, lithium when administered in the diet for up to 4 months showed a significant reduction in the thyroidal 131 I uptake after 2 h and 24 h which is in agreement with our earlier reports [16,23]. Lithium has previously been reported [29] to cause a marked decrease in the rate of synthesis of 131 I iodothyronines.…”

“…They also reported that when lithium treatment was prolonged for 6 months, no change was observed in the thyroidal 131 I uptake. The normalization of uptake under lithium conditions given for 6 months, as indicated in our earlier study [23], might be explained by the hypothesis of Sedvall et al [18], which indicates that 131 I uptake may be regulated by TSH. The increased T biol of 131 I in the thyroid following lithium treatment observed in the present study is supported by other authors [31] and resulted in the use of lithium as an adjunct to radioiodine therapy in thyrotoxic patients.…”

“…Hullin and Johnson [30] also observed a significant decrease in thyroidal 131 I uptake under chronic lithium conditions. Further, Dhawan et al [23] demonstrated that thyroidal 131 I uptake in rats measured after 2 h and 24 h decreased significantly following lithium treatment (1.1 g per kg diet) for up to 4 months. They also reported that when lithium treatment was prolonged for 6 months, no change was observed in the thyroidal 131 I uptake.…”

“…Similarly, Turner et al [32] found that low-dose lithium therapy increased the retention of a standard therapeutic dose of 131 I in the thyroid gland. An increase in 131 I T biol was reported to persist for up to 4-6 months following lithium treatment [16,23].…”

“…Occasional hyperthyroidism has, however, also been related to lithium use. Dhawan et al [23] showed that lithium treatment may enhance the retention of 131 I in the rat thyroid. The effect of lead and lithium, separately and in combination, on the levels of essential and non-essential elements in rat blood, liver and brain have been reported elsewhere [24,25,26,27].…”