| Author/Editor | Koritnik, Katarina | |
| Title | Vpliv tiroksina na postiradiacijsko karcinogenezo pri podganah | |
| Translated title | The role of thyroxin in radiation carcinogenesis in rats | |
| Type | monografija | |
| Place | Ljubljana | |
| Publisher | Medicinska fakulteta | |
| Publication year | 1999 | |
| Volume | str. 98 | |
| Language | slo | |
| Abstract | The aim of this study was to test the hypothesis on the protective role of thyroxin administration before and during irradiation in the occurrence of thyroid carcinoma in rats. Application of thyroxin before and during irradiation was expected to decrease production of thyrotropin by the hypophyseal feedback mechanism, caused by radiation damage of thyroid tissue. Stabilizing the thyroid cells in this way during irradiation would thus make them less radiosensitive. In the experiment, we first distributed 81 Wistar strain rats of both sexes, 3 - 4 weeks old into two groups, i. e. thyroxin (T4) and water (H20). The T4 rats were injected 1 % thyroxin solution (0.01 mg / 100 g body weight) twice a day for 15 days, while the H20 rats received water in the same way. After ten days the two ma.in groups were divided each into two subgroups, the rats from both irradiated subgroups (T4/IRR and (H20/IRR) received 10 Gy to the neck area. They were irradiated on a telecobalt machine for five consecutive days with one direct field. During two year's follow - up all moribund animals were sacrificed and their thyroid glands were taken, the rest of the thyroid glands were taken at the end of the experiment. All glands were pathohistologically and stereologically analysed. Besides, all suspicious and enlarged extrathyroid organs and tissues were examined and the occurrence of tumors was noted. It was established, that in the irradiated group of rats without thyroxin, significantly (P = 0.01 ) more carcinomas occurred than in the irradiated group without thyroxin. Thyroxin and irradiation had significant influence on the survival of rats, irradiation significantly shortened the survival while thyroxin prolonged it. Absolute volumes of glands with carcinomas were greater than of the glands with adenomas, which were greater than normal glands, but the difFerences were not statistically significant. (abstract truncated at 2000 characters) | |
| Descriptors | THYROXINE THYROID GLAND RADIATION TOLERANCE THYROID NEOPLASMS RATS, WISTAR NEOPLASMS, RADIATION-INDUCED HYPERPLASIA ADENOMA CARCINOMA, PAPILLARY, FOLLICULAR |