A method for the determination of type I iodothyronine deiodinase activity in liver and kidney using 125I-labelled reverse triiodothyronine as a substrate
✍ Scribed by Christine S. Hotz; Bartholomeus Belonje; Dennis W. Fitzpatrick; Mary R. L'abbé
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 620 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0009-9120
No coin nor oath required. For personal study only.
✦ Synopsis
Objectives: A detailed method for the determination of iodothyronine deiodinase type I (DI-I) activity is described. The objective of the present method developmev, t was to consolidate the effective procedures of previous methods and produce an efficient assay that can be easily reproduced.
Design and methods:
This method uses a 5',-1251-labelled rT3 as substrate and ion-exchange chromatography to separate released ionic iodine. Released 1251-collected in the eluate is counted, and the results used to calculate DI-I activity. Results: Results were found to be linear for tissue homogenates containing 3-11 mg protein, mL -1 . Day-to-day coefficient of variation of liver homogenate was determined to be 13%.
Conclusions:
This method was found to be reliable, reproducible, and sample sizes as small as 10 pL could be readily assayed. The use of centrifuge filter units to contain the ion-exchange medium decreased handling of the material, and potential sources of error.