In order to interpret pathologic mechanism of free radicals and thyroid hormone metabolism in cattle iodine and selenium deficiency, 20 heads of yellow cattle were selected from NiuJia town, Wu Chang City, Heilongjian...In order to interpret pathologic mechanism of free radicals and thyroid hormone metabolism in cattle iodine and selenium deficiency, 20 heads of yellow cattle were selected from NiuJia town, Wu Chang City, Heilongjiang Province, China, and were randomly devided into 4 groups with 5 for each. ① supplemented with 0.7 mg·kg -1 iodine(potassium iodine), ② supplemented with 0.2 mg·kg -1 selenium (sodium selenite), ③ supplemented with 0.7 mg·kg -1 iodine(potassium Iodine) plus 0.2 mg·kg -1 selenium (sodium selenite) per day for 30 days, respectively. ④control group. The whole blood glutathione peroxidase (GSH-px) and catalase (CAT) activities, free radicals (FR) concentration, erythrocyte superoxide dismutase (SOD) activity and molonaldehyde (MDA) concentration, the serum triiodothyronine (T 3)、thyroxine (T 4) and thyrotropin (TSH) were determined on the day of supplementation day-0 and day-30, respectively. It was showed that average iodine concentration in drinking water and diet were 3.82 μg·L -1 and 0.285mg·kg -1 , respectively, Diet selenium was 0.0498mg·kg -1 , Serum protein bound iodine(PBI) was 7.02 μg·100 mL, Blood selenium was 0.14 mg·L -1 , the schoolchildren′s goiter was 21.8%. It indicated that iodine and selenium were deficient in the investigated area. Whole blood GSH-px and CAT activities and serum T 3 concentration were significantly higher (P< 0.01 ), FR concentration and serum TSH were significantly lower(P<0.01) in the first three groups than that of the control, T 4 content in the first group was higher(P<0.05), T 4 was also higher (P>0.05) in the second group. and lower in the third group. The SOD and MDA in erythrocyte were not changed during the experimental period, The results also showed that GSH-px and CAT activities were increased, and FR decreased oberviously in the third group more than the other two groups, In addition, Thyroid hormone metabolism was more coincided with the physiologic status in the third group. the iodine and the selenium played an important role in the pathologic process of free radical metabolic disorder. selenium not only had the function of antioxidation by derectly scavenging free radicals, but also affected through GSH-px and CAT activities. iodine deficiency results in the Goiter, selenium deficiency aggravated iodine deficiency, Iodine and the selenium were dependent and restrained each other in the course of free radicals and thyroid hormone metabolism with a synergistic state.展开更多
Ammonium perchlorate （AP）, mainly used as solid propellants, was reported to interfere with homeostasis via competitive inhibition of iodide uptake. However, detailed mechanisms remain to be elucidated. In this stud...Ammonium perchlorate （AP）, mainly used as solid propellants, was reported to interfere with homeostasis via competitive inhibition of iodide uptake. However, detailed mechanisms remain to be elucidated. In this study, AP was administered at 0, 130, 260 and 520 mg/kg every day to 24 male SD rats for 13 weeks. The concentrations of iodine in urine, serum thyroid hormones levels, to- tal iodine, relative iodine and total protein, and malondialdehyde （MDA）, superoxide dismutase （SOD） and catalase （CAT） activity in thyroid tissues were measured, respectively. Our results showed that high-dose perchlorate induced a significant increase in urinary iodine and serum thyroid stimu- lating hormone （TSH）, with a decrease of total iodine and relative iodine content. Meanwhile, free thyroxine （FT4） was decreased and CAT activity was remarkably increased. Particularly, the CAT activity was increased in a dose-dependent manner. These results suggested that CAT might be en- hanced to promote the synthesis of iodine, resulting in elevated urinary iodine level. Furthermore, these findings suggested that iodine in the urine and CAT activity in the thyroid might be used as biomarkers for exposure to AP, associated with thyroid hormone indicators such as TSH. FT4.展开更多
本文对碘缺乏地区人群进行了 TRH 兴奋试验的研究。通过对18例无甲肿居民、18例甲肿居民和17例神经型克汀病者的 TSH 对 TRH 应答性的观察,表明经过3年的供碘,病区大部分人群的甲状腺功能得以改善,但部分人群出现 TSH 对 TRH 应答性低钝...本文对碘缺乏地区人群进行了 TRH 兴奋试验的研究。通过对18例无甲肿居民、18例甲肿居民和17例神经型克汀病者的 TSH 对 TRH 应答性的观察,表明经过3年的供碘,病区大部分人群的甲状腺功能得以改善,但部分人群出现 TSH 对 TRH 应答性低钝,其中甲肿者占38.9%,无甲肿者占44.4%。本次调查未发现现症甲状腺功能低下者,但部分无现症甲低症的神经型克汀病者有激素性甲低的实验室依据。展开更多
Background Type 1 deiodinase （D1） plays an important role in the metabolism of thyroid hormone and has close relationship with thyroid function. In this study we explore the effects of iodine intake on D1 activity a...Background Type 1 deiodinase （D1） plays an important role in the metabolism of thyroid hormone and has close relationship with thyroid function. In this study we explore the effects of iodine intake on D1 activity and its mRNA expression and its possible mechanism. Methods Forty-eight Wistar rats were randomly divided into six groups with 8 in each： low iodine （LI）, normal iodine （NI）, five-fold iodine （HI5）, ten-fold iodine （HI10）, fifty-fold iodine （HI50）, one hundred-fold iodine （HI100） group. Three months, six months and twelve months after admistration of potassium iodate, they were sacrificed and thyroids were excised. The expression of D1 mRNA in the thyroid tissue was determined by RT-PCR and D1 activity was analyzed by ^125I-rT3 as substrate. The thyroid hormone was measured with radioimmunoassay method. Results Compared with NI group, D1 mRNA expression in LI groups slightly decreased, and D1 activity greatly increased. Both T3 and T4 in thyroid tissue significantly decreased, but the T3/T4 ratio increased. D1 mRNA expression decreased in all HI groups, and D1 activity was significantly lower in HI groups. There was a tendency of decrease in D 1 activity with increased doses of iodine intakes. There was no significant difference in T4 in thyroid tissue between HI groups and NI group, but a tendency of decrease in T3 level was found in all HI groups. Conclusions In the case of iodine deficiency, D 1 activity increased greatly in order to convert more T4 to T3. Excess iodine can inhibit both D1 mRNA expression and its activity to protect organism from being injured by excessive T3.展开更多
文摘In order to interpret pathologic mechanism of free radicals and thyroid hormone metabolism in cattle iodine and selenium deficiency, 20 heads of yellow cattle were selected from NiuJia town, Wu Chang City, Heilongjiang Province, China, and were randomly devided into 4 groups with 5 for each. ① supplemented with 0.7 mg·kg -1 iodine(potassium iodine), ② supplemented with 0.2 mg·kg -1 selenium (sodium selenite), ③ supplemented with 0.7 mg·kg -1 iodine(potassium Iodine) plus 0.2 mg·kg -1 selenium (sodium selenite) per day for 30 days, respectively. ④control group. The whole blood glutathione peroxidase (GSH-px) and catalase (CAT) activities, free radicals (FR) concentration, erythrocyte superoxide dismutase (SOD) activity and molonaldehyde (MDA) concentration, the serum triiodothyronine (T 3)、thyroxine (T 4) and thyrotropin (TSH) were determined on the day of supplementation day-0 and day-30, respectively. It was showed that average iodine concentration in drinking water and diet were 3.82 μg·L -1 and 0.285mg·kg -1 , respectively, Diet selenium was 0.0498mg·kg -1 , Serum protein bound iodine(PBI) was 7.02 μg·100 mL, Blood selenium was 0.14 mg·L -1 , the schoolchildren′s goiter was 21.8%. It indicated that iodine and selenium were deficient in the investigated area. Whole blood GSH-px and CAT activities and serum T 3 concentration were significantly higher (P< 0.01 ), FR concentration and serum TSH were significantly lower(P<0.01) in the first three groups than that of the control, T 4 content in the first group was higher(P<0.05), T 4 was also higher (P>0.05) in the second group. and lower in the third group. The SOD and MDA in erythrocyte were not changed during the experimental period, The results also showed that GSH-px and CAT activities were increased, and FR decreased oberviously in the third group more than the other two groups, In addition, Thyroid hormone metabolism was more coincided with the physiologic status in the third group. the iodine and the selenium played an important role in the pathologic process of free radical metabolic disorder. selenium not only had the function of antioxidation by derectly scavenging free radicals, but also affected through GSH-px and CAT activities. iodine deficiency results in the Goiter, selenium deficiency aggravated iodine deficiency, Iodine and the selenium were dependent and restrained each other in the course of free radicals and thyroid hormone metabolism with a synergistic state.
基金supported by the National Natural Science Foundation of China(No.30972452)
文摘Ammonium perchlorate （AP）, mainly used as solid propellants, was reported to interfere with homeostasis via competitive inhibition of iodide uptake. However, detailed mechanisms remain to be elucidated. In this study, AP was administered at 0, 130, 260 and 520 mg/kg every day to 24 male SD rats for 13 weeks. The concentrations of iodine in urine, serum thyroid hormones levels, to- tal iodine, relative iodine and total protein, and malondialdehyde （MDA）, superoxide dismutase （SOD） and catalase （CAT） activity in thyroid tissues were measured, respectively. Our results showed that high-dose perchlorate induced a significant increase in urinary iodine and serum thyroid stimu- lating hormone （TSH）, with a decrease of total iodine and relative iodine content. Meanwhile, free thyroxine （FT4） was decreased and CAT activity was remarkably increased. Particularly, the CAT activity was increased in a dose-dependent manner. These results suggested that CAT might be en- hanced to promote the synthesis of iodine, resulting in elevated urinary iodine level. Furthermore, these findings suggested that iodine in the urine and CAT activity in the thyroid might be used as biomarkers for exposure to AP, associated with thyroid hormone indicators such as TSH. FT4.
文摘本文对碘缺乏地区人群进行了 TRH 兴奋试验的研究。通过对18例无甲肿居民、18例甲肿居民和17例神经型克汀病者的 TSH 对 TRH 应答性的观察,表明经过3年的供碘,病区大部分人群的甲状腺功能得以改善,但部分人群出现 TSH 对 TRH 应答性低钝,其中甲肿者占38.9%,无甲肿者占44.4%。本次调查未发现现症甲状腺功能低下者,但部分无现症甲低症的神经型克汀病者有激素性甲低的实验室依据。
基金This study was supported by grants from the National Nature Science Foundation of China (No.30230330) and Tianjin Technology Development Project (No.05YFGDSF02700).
文摘Background Type 1 deiodinase （D1） plays an important role in the metabolism of thyroid hormone and has close relationship with thyroid function. In this study we explore the effects of iodine intake on D1 activity and its mRNA expression and its possible mechanism. Methods Forty-eight Wistar rats were randomly divided into six groups with 8 in each： low iodine （LI）, normal iodine （NI）, five-fold iodine （HI5）, ten-fold iodine （HI10）, fifty-fold iodine （HI50）, one hundred-fold iodine （HI100） group. Three months, six months and twelve months after admistration of potassium iodate, they were sacrificed and thyroids were excised. The expression of D1 mRNA in the thyroid tissue was determined by RT-PCR and D1 activity was analyzed by ^125I-rT3 as substrate. The thyroid hormone was measured with radioimmunoassay method. Results Compared with NI group, D1 mRNA expression in LI groups slightly decreased, and D1 activity greatly increased. Both T3 and T4 in thyroid tissue significantly decreased, but the T3/T4 ratio increased. D1 mRNA expression decreased in all HI groups, and D1 activity was significantly lower in HI groups. There was a tendency of decrease in D 1 activity with increased doses of iodine intakes. There was no significant difference in T4 in thyroid tissue between HI groups and NI group, but a tendency of decrease in T3 level was found in all HI groups. Conclusions In the case of iodine deficiency, D 1 activity increased greatly in order to convert more T4 to T3. Excess iodine can inhibit both D1 mRNA expression and its activity to protect organism from being injured by excessive T3.
