Influence of nicotinamide on the radiosensitivity of normal and goitrous thyroid in the rat
| Autor: | L. Krawiec, M. Viaggi, Mario A. Pisarev, Guillermo Juvenal, M. Agote, E. Kreimann, Maria Alejandra Dagrosa |
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| Rok vydání: | 2002 |
| Předmět: |
Niacinamide
medicine.medical_specialty Radiosensitizer Goiter endocrine system diseases Endocrinology Diabetes and Metabolism Thyroid Gland Radiation Tolerance Iodine Radioisotopes chemistry.chemical_compound Endocrinology Antithyroid Agents Internal medicine Medicine Animals Radiosensitivity Rats Wistar Thyroid cancer Cell Nucleus Adenosine Diphosphate Ribose Methimazole Nicotinamide business.industry Therapeutic effect Thyroid medicine.disease Rats Adenosine diphosphate medicine.anatomical_structure chemistry Regional Blood Flow Female business Rubidium Radioisotopes |
| Zdroj: | Thyroid : official journal of the American Thyroid Association. 11(11) |
| ISSN: | 1050-7256 |
| Popis: | Radioiodine is used to treat thyroid cancer and hyperthyroidism. In order to reduce radiation hazard to the patient and to people in contact with the patient it would be desirable to obtain the same therapeutic effect with lower activities of the radioisotope. This could be achieved by the simultaneous administration of a compound that increases tissue radiosensitivity. In this study we analyzed the use of nicotinamide (NA) as a radiosensitizer to radioiodine, to increase 131I efficacy. NA administered during 30 days to Wistar rats failed to alter thyroid weight. The influence of NA on radiothyroidectomy induced by increasing doses of 131I was examined in otherwise nontreated rats. NA produced a significant increase in the ablation caused by radioiodine. Goiter was then induced by the administration of methylmercaptoimidazol (MMI) to rats, followed by the treatment with radioiodine with and without simultaneous administration of NA. Thyroid weight per 100 g of body weight ratio was not changed by NA alone; 131I administration caused a 25% decrease in goiter size, while 131I plus NA produced a reduction of the ratio of 46% (p < 0.01 vs. NA). No changes were observed in adenosine diphosphate (ADP)-ribosilation of thyroid nuclear protein in NA-treated rats. Thyroid blood flow (determined by 86Rb uptake) was increased by 84% by NA. In conclusion, nicotinamide has a significant radiosensitizing effect to 131I both in normal and goitrous rats. This action is because of an increase in thyroid blood flow, which probably enhances tissue oxgenation. |
| Databáze: | OpenAIRE |
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