Abstract
The effects of a malignant tumor (Walker 256) on thyroid hormone economy were assessed. PBI in serum was considerably reduced in tumor-bearing animals. Urinary excretion of 131I in tumorous rats isotopically equilibrated with 131I-labeled T4 (5 μg/day) was significantly greater than in corresponding control animals, indicating that the deiodination of T4 was increased. This increase was associated with a reduction in the concentration of 131I-T4 in serum; thus, the rate of clearance of T4 from plasma was greatly increased in the tumorous rats. This increase was due, not only to the enhanced rate of deiodination, but also to an increased rate of clearance by the gastro-intestinal pathway. The increased rate of clearance was apparently not the result of a primary stimulation of intracellular deiodinating mechanisms; no change in the in vitro deiodination of T4 in tissues of tumorous animals was observed and deiodination by the tumorous tissue itself was minimal. In tumorous animals, increases were noted in ...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
