Effect of cadmium on T4 outer ring monodeiodination by rat liver
| Autor: | Toshiro Sakurada, Shintaro Saito, Hiroshi Saito, Koru Yoshinaga, Naoko Sugihira, Michiko Suzuki, Katsumi Yoshida |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
medicine.medical_specialty
chemistry.chemical_element Peptide hormone In Vitro Techniques Biochemistry Dithiothreitol Subcutaneous injection chemistry.chemical_compound Blood serum In vivo Internal medicine medicine Animals General Environmental Science Cadmium Triiodothyronine Radioimmunoassay Rats Inbred Strains Rats Thyroxine Endocrinology chemistry Liver Propylthiouracil Female Metallothionein |
| Zdroj: | Environmental research. 42(2) |
| ISSN: | 0013-9351 |
| Popis: | The effect of cadmium on thyroxine (T/sub 4/) outer ring monodeiodination was studied in vivo and in vitro in the rat liver. One microgram of T/sub 4/ was incubated with rat liver homogenates in 50 mM Tris-HCl buffer, pH 7.4, with or without 0.5, 5, and 50 mM dithiothreitol (DTT) for 60 min in the presence of 10/sup -8/ to 10/sup -3/ M CdCl/sub 2/, and the amount of 3,5,3'-triiodothyronine (T/sub 3/) produced was determined by a specific radioimmunoassay. Subcutaneous injection of CdCl/sub 2/, 1 mg/kg BW/day, 5 days a week for 10 weeks, to the rats resulted in a significant reduction in serum T/sub 3/ concentration (by 37%) and hepatic T/sub 3/ production from T/sub 4/ (by 78 to 92%). In vitro addition of 1 ..mu..M to 1 mM CdCl/sub 2/ to liver homogenates caused a concentration-dependent reduction in T/sub 3/ generation. Without DTT a 50% reduction in the T/sub 4/ to T/sub 3/ converting activity was caused by 4 x 10/sup -6/ M CdCl/sub 2/. DTT (0.5 to 50 mM) partially restored T/sub 3/ generation roughly in a concentration-dependent manner. These results indicate that cadmium has some effects on the metabolism of thyroid hormone. |
| Databáze: | OpenAIRE |
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