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 1311 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 . I g per kg of diet) for 7 days. However, continuing this diet for 10 days inhibited thyroid uptake and increased the retention of 131 I. Uptake remained suppressed for up to 4 months after lithium treatment and continuing this treatment for 6 months did not result in any significant change in 1311 uptake by the thryoid. Lithium treatment for 10 days increased the biological and effective half-life of 13l I in the thyroid and this increase continued for the 6 months treatment period. The dose of 13l I delivered to the thyroid was significantly lower after 10 days and I month of lithium treatment but there was no change in this dose after 2 and 4 months of treatment. However, there was a significant increase after 6 months.