Possible Interaction: Iodides and Propylthiouracil

“ PTU inhibits oxidation of iodide by TPO and therefore effectively limits the production of thyroid hormone.”

“The iodide organification step can be inhibited by propylthiouracil and methimazole, which are TPO enzyme inhibitors.”

“After 20-h incubation, iodide production was inhibited in the presence of ouabain (0.5 mmol/L), propylthiouracil (100 mumol/L), or a monoclonal antibody (81-1A1-10; ascites dilution, 1:200) directed against thyroid hormone transport systems in rat hepatocytes.”

“ Iodide but not perchlorate decreased the rate of metabolism of 35 S-propylthiouracil in the thyroid gland.”

“The inhibitory effects of iodide on NIS mRNA expression were abolished by propylthiouracil and dithiothreitol.”

“The stimulatory effects of MMI and PTU can be suppressed by iodide and do not occur when protein synthesis is inhibited by cycloheximide.”

“In the group of hyperthyroidism simultaneously given both PTU and iodide (300 mg/PTU and 1 mg/iodine), these thyroid function parameters decreased as well as in the group treated with PTU alone for more than two weeks.”

“These results suggested strongly that iodide alone was not an adequate therapy for hyperthyroidism as well known and they were also compatible with the idea that the concomitant administration of PTU and iodide was more effective in the early phase of therapy of hyperthyroidism than PTU alone.”

“However, further increase of the dose of stable iodide caused the T/S of propylthiouracil (PTU)-treated rats to drop (VanderLaan and VanderLaan, 1947; Wyngaarden et al., 1953).”

“Some authors have proposed that iodide , given after methimazole or propylthiouracil , is capable of inducing apoptosis in thyroid cells and that anti-thyroid drugs can modulate the expression of apoptosis components such as Fas and its ligand (Fas-L).”

“It is suggested (1) that PTU impairs thyroidal uptake of iodide , (2) that endogenous TSH stimulates release from the thyroid of inorganic iodide as well as of thyroid hormones, and (3) that inorganic iodide released by the thyroid has a much shorter biological half-life than hormone-bound iodine.”