Theophylline Increases the Uptake of Radioiodine by Mouse Thyroid.
10.3346/jkms.2004.19.5.704
- Author:
Jong Min LEE
1
;
Patrizio CATUREGLI
;
Paul W LADENSON
Author Information
1. Department of Internal Medicine, The Catholic University of Korea, Medical College, Seoul, Korea. drjmlee@catholic.ac.kr
- Publication Type:Original Article
- Keywords:
Theophylline;
Iodine Radioisotopes;
Cyclic AMP;
Thyroid Gland
- MeSH:
Animals;
Blood Proteins/pharmacology;
Cells, Cultured;
Cyclic AMP/metabolism;
Female;
Iodine Radioisotopes/*diagnostic use/pharmacokinetics;
Mice;
Mice, Inbred C57BL;
Theophylline/*pharmacology;
Thyroid Gland/cytology/*metabolism;
Vasodilator Agents/*pharmacology
- From:Journal of Korean Medical Science
2004;19(5):704-709
- CountryRepublic of Korea
- Language:English
-
Abstract:
Diagnostic and therapeutic use of radioiodine in the management of thyroid disorders depends on the ability of thyroid cells to concentrate radioiodine, a process that is regulated by the intracellular increase in cAMP. We hypothesized that theophylline, a drug known to increase intracellular cAMP via inhibition of phosphodiesterase, could increase thyroidal radioiodine uptake. We tested this effect in vivo, using C57BL/6j mice, and in vitro, using Fisher rat thyroid (FRTL-5) cells. One mouse received 2.5mg theophylline i.p., whereas a control mouse received only saline. Twenty-hours after theophylline, mice were injected with 10mu Ci Na(125)I in 0.1 mL saline through the tail vein. Mean thyroidal (125)I activity was 3.3-fold higher in theophylline-treated mice than in their respective controls. Radioiodine uptake and intracellular cAMP production of FRTL-5 cells were increased by a relatively low concentration of theophylline (1mu M). Intracellular cAMP increased up to 30 min and then declined in response to 1mu M theophylline. Sera from theophylline-treated mice stimulated (125)I uptake and intracellular cAMP production by FRTL-5 cells. These findings show that theophylline can enhance radioiodine uptake by thyrocytes in vivo and in vitro. The in vitro effects of theophylline on both radioiodine uptake and cAMP production in a dose-dependent manner are consistent with an action mediated by phosphodiesterase inhibition.
