TY - JOUR T1 - THE EFFECT OF ACUTE AND CHRONIC ADMINISTRATION OF CHLORPROMAZINE ON THE I<sup>131</sup> DISTRIBUTION IN NORMAL RATS JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 269 LP - 276 VL - 138 IS - 2 AU - Ralph Wiseman, Jr. Y1 - 1962/11/01 UR - http://jpet.aspetjournals.org/content/138/2/269.abstract N2 - After a single intraperitoneal dose of 25 mg/kg of body weight of chlorpromazine (CPZ) in the rat a 40.3% decrease in the 6-hour I131 uptake by the thyroid was observed. Other changes encountered in these animals in 6 hours were a 92.7% decrease in urinary excretion of I131, a 29.7% increased retention of I131 in the carcass and a 58.0% reduction in urine volume, all changes having P &lt; .001. This dose of CPZ in trained rats produced a profound hypotension of 27-hour duration while a single 1 mg/kg of body weight dose of CPZ had no effect on blood pressure. CPZ was administered to rats at a dose of 25 mg/kg of body weight for 12 days. Sixty-six hours after the last dose of CPZ the 6-hour I131 uptake by the thyroid gland was decreased 40.4%. The significant changes in I131 distribution after a single dose of 25 mg/kg of body weight of CPZ were interpreted as resulting primarily from a sustained hypotension produced by this dose of CPZ and secondly to decreased TSH liberation, a direct blockage of the iodide-trapping mechanism of the thyroid gland or both. The interference with the I131 uptake in the chronic animals at this dose of CPZ was not attributable to the hypotension but rather to suppressed TSH secretion, blockage of iodide trapping of the thyroid or both. A single intraperitoneal dose of 1 mg/kg of body weight of CPZ exhibited no effect on the 6hour distribution of I131 in the rat. When this dose of CPZ was given daily for 89 days to rats, no effect was observed on the 6-hour I131 distribution. ER -