BIOKINETICS OF I-131 IN RAT-THYROID FOLLOWING LEAD AND LITHIUM SUPPLEMENTATION

The impact of lead as an environmental pollutant on the I-131 uptake a nd retention in rat thyroid was assayed alone and in combination with lithium treatment. Lead treatment significantly stimulated the 2- and 24-h uptake of I-131 in the thyroid, and the 24-h uptake showed the ma ximum stimulation after 3 mo of lead treatment. On the contrary, lithi um supplementation reduced the uptake significantly and the maximum de crease was noticed after 2 mo of lithium administration. Further, simu ltaneous lead and lithium treatment resulted in more pronounced increa se in the uptake of I-131 by the thyroid, which was maximum after 3 mo of combined treatment. The thyroidal biological half-life of I-131 (T -biol) was found to be increased significantly following lead and lith ium treatments when given separately. Interestingly, combined lead and lithium treatment given up to 2 mo further prolonged the T-biol of I- 131, thus reflecting its increased retention.