Effect of high bromide levels in the organism on the biological half-life of iodine in the rat

In experiments on rats, a significant influence of an extraordinarily high bromide intake on the whole-body biological half-life of iodine was established. Very high bromide intake (1) decreased the amount of radioiodide accumulated in the thyroid, (2) changed the proportion between the amount of iodine retained in the thyroid and the total amount of absorbed iodine, (3) significantly shortened the biological half-life of iodine in the thyroid from approximately 101 h to 33 h in animals maintained on an iodine-sufficient diet and from 92 h to about 30 h in rats fed a low-iodine diet, and (4) changed the time-course (added a further phase) of iodine elimination from the body. These changes were caused, with high probability, by an increase of iodine elimination by kidneys due to an excess of bromide. The overall picture of iodine elimination in animals fed the low-iodine diet was similar to that in animals maintained on iodine-sufficient diet. Presented in part at the 20th Workshop on Macro and Trace Elements held in Jena (Germany) on December 1–2, 2000.     

Metabolism of bromide and its interference with the metabolism of iodine

The present knowledge about the metabolism of bromide with respect to its goitrogenic effects, including some conclusions drawn from our recent research on this subject, is reviewed. Firstly, the biological behavior of bromide ion is compared with that of chloride and iodide. Secondly, the details about distribution and kinetics of bromide ions in the body and in 15 different organs and tissues of the rat are given. Significant correlation between the values of the steady-state concentration of bromide in the respective tissue and of the corresponding biological half-life was found in most tissues examined. A remarkably high concentration of radiobromide was found in the skin, which represents, due to its large mass, the most abundant depot of bromide in the body of the rat. Thirdly, the effects of excessive bromide on the rat thyroid are summarized, along with the interference of exogenous bromide with the whole-body metabolism of iodine. It is suggested that high levels of bromide in the organism of experimental animals can influence their iodine metabolism in two parallel ways: by a decrease in iodide accumulation in the thyroid and skin (and in the mammary glands in lactating dams), and by a rise in iodide excretion by kidneys. By accelerating the renal excretion of iodide, excessive bromide can also influence the pool of exchangeable iodide in the thyroid. Finally, our recent results concerning the influence of high bromide intake in the lactating rat dam on iodine and bromide transfer to the suckling, and the impact of seriously decreased iodine content and increased bromide concentration in mother's milk on the young are discussed. We must state, however, that the virtue of the toxic effects of excessive bromide on the thyroid gland and its interference with the biosynthesis of thyroid hormones, as well as the exact mechanism of bromide interference with postnatal developmental processes remains to be elucidated.     

High bromide intake affects the accumulation of iodide in the rat thyroid and skin

The effect of a high bromide intake on the kinetics of iodide uptake and elimination in the thyroid and skin of adult male rats was studied. In rats fed a diet with sufficient iodine supply (>25 μg I/d), the iodide accumulation in the skin predominated during the first hours after ¹³¹I -iodide application. From this organ, radioiodide was gradually transferred into the thyroid. A high bromide intake (>150 mg Br⁻/d) in these animals led to a marked decrease in iodide accumulation, especially by the thyroid, because of an increase in iodide elimination both from the thyroid and from the skin. In rats kept under the conditions of iodine deficiency (<1 μ I/d), the iodide accumulation in the thyroid, but not in the skin, was markedly increased as a result of a thyrotropic stimulation. The effect of a high bromide intake (>100 mg Br⁻/d) in these animals was particularly pronounced because the rates of iodide elimination were most accelerated both from their thyroid and from their skin. Presented in part at the 20th Workshop on Macro and Trace Elements held in Jena (Germany) on December 1–2, 2000.     

Effect of enhanced bromide intake on the concentration ratio I/Br in the rat thyroid gland

Biological Trace Element Research - Interaction of bromine with iodine was studied in the rat thyroid gland under the conditions of different bromide intake. Bromine and iodine in the thyroid dry...     

Interaction of bromine with iodine in the rat thyroid gland at enhanced bromide intake

In experiments with rats, we have found that at enhanced intake of bromide, bromine does not replace chlorine in the thyroid; it replaces iodine. Under our experimental conditions, more than onethird of the iodine content in the thyroid was replaced by bromine. In the thyroid, bromine probably remained in the form of bromide and, in proportional to its increased concentration, the production of iodinated thyronines decreased, with the sum of the iodine and bromine concentrations being constant at the value of 20.51±1.16 μmol/g dry wt of the thyroid. In contrast to other organs, the biological behavior of bromine in the thyroid is not similar to the biological behavior of chlorine but resembles more that of iodine.     

Effect of long-term administration of arsenic (III) and bromine with and without selenium and iodine supplementation on the element level in the thyroid of rat

The aim of this study was to evaluate the influence of arsenic and bromine exposure with or without iodine and selenium supplementation on the element level in the thyroid of rats. Four major groups of Wistar female rats were fed with respective diets: group A - standard diet, group B - iodine rich diet (10 mg I/kg food), group C - selenium rich diet (1 mg Se/kg) and group D - iodine and selenium rich diet (as in group B and C). Each group was divided into four subgroups per 7 animals each receiving either NaAsO(2) ip (6.5 mg.kg(-1) twice a week for two weeks and 3.25 mg.kg(-1) for six weeks) or KBr in drinking water (58.8 mg.l(-1)) for 8 weeks or combined administration of both substances. Remaining subgroup served as controls. After 8 weeks thyroid glands were analyzed by ICP-MS for As, Br, Se, and I content. The exposition of rat to arsenic or bromine causes the accumulation of these elements in the thyroid gland ( approximately 18 ppm of As, approximately 90 ppm of Br) and significantly affects iodine and selenium concentration in the thyroid. In iodine and/or selenium supplemented rats the bromine intake into the thyroid was lowered to approximately 50% of the level in unsupplemented animals. Also selenium thyroid level elevated due to KBr administration was lowered by iodine supplementation in the diet. The accumulation of arsenic in the thyroid was not influenced by selenium or iodine supplementation; however, As(III) administration increased iodine thyroid level and suppressed selenium thyroid level in selenium or iodine supplemented group of animals.     

Thyroid function and deiodinase activities in rats with marginal iodine deficiency

The hypothesis tested was whether marginal iodine deficiency for a period of 6 wk affects iodothyronine deiodinase activities in liver and brain of rats. Male rats were fed purified diets either deficient or sufficient in iodine; the diets were fed on a restricted basis (60% ofad libitum intake). Body weight gain of the two groups was comparable. Iodine deficiency was evidenced by increased thyroid weight (26%), reduced urinary iodine excretion (80%), and reduced plasma T₄ concentrations (22%). Activities of liver type I and brain type III deiodinase were unchanged, but the activity of type II deiodinase in brain was increased (28%) in the iodine-deficient rats. Food restrictionper se significantly lowered T₃ (30%) and T₄ (22%) concentrations in plasma and decreased type III deiodinase activity in brain (30%). These results indicate that in marginal iodine deficiency the activities of hepatic type I deiodinase and brain type III deiodinase are unchanged, whereas that of brain type II deiodinase is increased.     

不同剂量131I对分化型甲状腺癌患者摄碘率、甲状腺激素水平及生活质量的影响

摘要 目的：探讨不同剂量¹³¹I对分化型甲状腺癌（DTC）患者摄碘率、甲状腺激素水平及生活质量的影响。方法：选取2018年6月～2020年6月我院收治的DTC患者100例,均接受¹³¹I清甲治疗,根据放射剂量的不同分为小剂量组（100mci）和大剂量组（150mci）,例数均为50例。比较两组患者摄碘率、甲状腺激素水平、肝肾功能、生活质量和不良反应发生率。结果：小剂量组2 h、6 h、24 h的摄碘率高于大剂量组（P<0.05）。小剂量组的清甲率高于大剂量组（P<0.05）。两组治疗1个月后促甲状腺激素（TSH）、游离三碘甲状腺原氨酸（FT3）、甲状腺球蛋白（TG）水平下降（P<0.05）;小剂量组治疗1个月后TSH、FT3、TG水平低于大剂量组（P<0.05）。两组治疗前、治疗1个月后的组间、组内门冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、碱性磷酸酶（ALP）、血清尿素（Urea）、肌酐（Cr）、尿酸（UA）水平对比,差异均无统计学意义（P>0.05）。小剂量组的生活质量优良率高于大剂量组（P<0.05）。小剂量组的不良反应发生率低于大剂量组（P<0.05）。结论：不同剂量¹³¹I清甲治疗对DTC患者肝肾功能无明显影响,但选用100mci剂量可提高DTC患者摄碘率,减轻对甲状腺功能的损害,同时还可提高患者的生活质量,减少不良反应发生率。     

Influence of Laminaria japonica added to the diet on remote effects of radiation injuries

White rats were irradiated by both ¹³¹iodine, which was incorporated into the thyroid gland, and ¹³⁷cesium; these were dosed at about 10 and 6 Gy, respectively. A portion of the experimental animals was fed a diet enriched with powdered Laminaria japonica of known composition. In animals provided with this powder, the frequency of neoplasms was lessened, and the latent period for the major types of tumours was increased, compared to rats not given the powder. (*author for correspondence)     

Iodine Distribution in the Environment as a Limiting Factor for Roe Deer Antler Development

The iodine-containing hormones produced by the thyroid gland play a role in the complex neuro-hormonal regulation of antler development. The proper function of the thyroid depends on the adequate iodine supply of the organism, which is directly related to the iodine content of food and drinking water. The purpose of this study was to explore the connection between the iodine content of the water base, which has a strong correlation with the iodine concentration of environmental components available to animals, and the antler weight of roe deer (Capreolus capreolus) shot in Hungarian hunting areas. Using a general linear model, controlling for the collective effects of other environmental factors (deer population density, harvest rate, land use, and soil fertility information), the iodine content of the water base explained 51.4% of the total variance of antler weights. The results suggest that antler weights increase with increasing iodine concentration regardless of other factors; thus, the environmental iodine distribution can be a limiting factor suppressing roe deer performance assessed here as antler weight. Further experimental studies of controlled iodine uptake are needed to define the exact physiological iodine requirements of roe deer bucks.     

甲状腺根治术后不同剂量131I清甲治疗对分化型甲状腺癌患者唾液流率、骨代谢和生活质量的影响

目的:探讨甲状腺根治术后不同剂量131I清甲治疗对分化型甲状腺癌患者唾液流率、骨代谢和生活质量的影响。方法:选取2018年1月~2020年1月期间我院诊治的分化型甲状腺癌患者141例,根据随机数字表法分为低剂量组[治疗剂量为1.1~3.7GBq(30~100 mci)]、中剂量组[治疗剂量为3.7~5.5GBq(100~150 mci)]、高剂量组[治疗剂量为5.5~7.4GBq(150~200 mci)],各47例。对比三组患者唾液流率、骨代谢、生活质量、腮腺和颌下腺的摄取参数(UR)和排泌参数(ER)。结果:高剂量组、中剂量组腮腺、颌下腺的左侧UR、右侧UR、左侧ER、右侧ER均低于低剂量组,且高剂量组低于中剂量组(P<0.05)。三组治疗后静态唾液流率(UWSFR)、动态唾液流率(SWSFR)均较治疗前下降(P<0.05),高剂量组、中剂量组治疗后UWSFR、SWSFR低于低剂量组,且高剂量组低于中剂量组(P<0.05)。低剂量组、中剂量组的优良率高于高剂量组,且中剂量组高于低剂量组(P<0.05)。三组治疗前后、组间总Ⅰ型胶原氨基端前肽(PINP)、β-胶原降解产物(β-CTX)、骨密度(BMD)对比,差异均无统计学意义(P>0.05)。结论:不同剂量131I清甲治疗对分化型甲状腺癌患者的骨代谢无明显影响,但不同剂量131I清甲治疗均会影响患者唾液腺功能及生活质量,其中高剂量131I清甲对患者的影响最为显著。     

Iodine metabolism in the thyroid gland in chronic uranium poisoning]

The exchange of radioactive and stable iodine was studied for 21 days after the I131 injection in the thyroid gland and the blood of rats against the background of chronic uranium intoxication. The latter was accompanied by a decrease in the number of iodine-transport loci of the gland, as well as of the value of the intrathyroid iodine pool and of the stable iodine concentration in the thyroid tissue. The compensatory reaction of the thyroid gland was expressed in the increase of its mass and the rate of the thyroid metabolism as well.     

The experimental optimization of iodine prophylaxis for decreasing the radiation load from the accidental uptake of radioiodine]

As is proved by nuclear disaster in Chernobyl Nuclear Power Plant (NPP), iodine prophylaxis may be respected as one of the most urgent and effective methods of prevention of radiation injury of the thyroid gland in the population affected. Author has studied factors and methods of its efficacy and reliability. On the basis of experiments in rats, analytical ways of determination of the dietary iodine intake (iodine supply) of people living around NPP Paks (Hungary) as well as compartment modelling, experiments it is shown, that for optimisation of iodine prophylaxis in masses it is very important to increase the iodine supply up to the recommended values. Combined use of decreased doses of potassium iodide and perchlorate was found to be the optimal way for removal of radioiodine from pregnant organisms and their offsprings following accidental intake of radioiodine.     

Effect of radish (Raphanus sativus Linn.) on thyroid status under conditions of varying iodine intake in rats

Cruciferous plants viz. cabbage, cauliflower, turnip, radish, mustard etc. that contain goitrogenic/antithyroid substances, constitute a portion of regular human diet. The effect of chronic feeding of fresh and cooked radish, R. sativus under varying state of iodine intake on morphological and functional status of thyroid in albino rats was evaluated by thyroid gland morphology and histology, thyroid peroxidase activity, serum triiodothyronine, thyroxine and thyrotropin levels. The consumption pattern of iodine and goitrogens of cyanogenic origin was evaluated by measuring urinary iodine and thiocyanate levels respectively. After chronic radish feeding, increased weight of thyroid gland, decreased thyroid peroxidase activity, reduced thyroid hormone profiles and elevated level of thyrotropin were observed resembling a relative state of hypoactive thyroid gland in comparison to control even after supplementation of adequate iodine.     

Correlation Between Iodine Intake and Thyroid Function in Subjects with Normal Thyroid Function

Excessive iodine intake is known to induce hypothyroidism in people who have underlying thyroid disorders. However, few studies have been performed on subjects with normal thyroid function without a history of autoimmune thyroid disease. We hypothesized that high iodine intake may cause a subtle change in thyroid function even in subjects with normal thyroid function. We analyzed 337 subjects (64 men and 273 women; mean age, 49 years) who showed normal levels of thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (Tg-Ab) by measuring the urinary iodine excretion, free T4 (FT4), and thyroid-stimulating hormone (TSH). The results showed urinary iodine excretion had negative correlation with FT4 (γ = −0.11, p = 0.043) and showed a positive trend with TSH (γ = 0.10, p = 0.068). We found that 61.7% of subjects had circulating TPO-Ab within normal reference range. In all subjects, TPO-Ab levels were negatively correlated with FT4 (γ = −0.17, p = 0.002) and positively with TSH (γ = 0.13, p = 0.021). In conclusion, high iodine intake can negatively affect thyroid hormone levels in subjects with normal thyroid function. Population-based study will be helpful for further clarification.     

Compartmental models for human iodine metabolism

Compartmental models for the various aspects of human iodine metabolism are reviewed, emphasizing the role of Mones Berman in the development of this field. The review first presents published submodels for the peripheral distribution of inorganic iodine, for the thyroidal iodide trapping function, and for the peripheral distribution and metabolism of the thyroid hormones. Approaches to improving understanding of the physiology of the thyroid gland itself through compartmental modeling techniques are then discussed in more detail. The three submodels described above are incorporated into overall models of thyroid iodine metabolism after being simplified to various degrees. Previously published models for thyroid-gland radioiodine metabolism, as well as current work in progress, are illustrated by attempting to fit the models to data from a single (previously unpublished) detailed prolonged ¹²⁵I feeding experiment in a normal human subject. Published thyroid gland models reviewed include: (1) the usual presentation, where the thyroid is a single homogeneous iodine compartment; (2) the model of DeGroot and colleagues, where thyroidal iodine is presented as MIT, DIT, T3, and T4, each with an active and linked storage compartment; (3) the thyroid model developed by Berman and colleagues, with less chemical subcategorization but incorporating a delay compartment, in which a fraction of the iodinated material in the thyroid is partially or completely inaccessible to secretion during the delay; and the later updating of Berman's model to include a thyroidal iodide recirculation pool. The experimental data presented fits most of these models for the first 1–2 weeks, but the fit could not be extended to longer data collection times. To overcome this shortcoming, a new thyroid gland model is introduced. It is based on the latest Berman model but describes thyroglobulin metabolism as incorporating multiple delay compartments of various time periods. The overall fit of the long term data is better with this model construct than with any of the published models. It appears that a complex thyroidal substructure, such as that of the multidelay model under development, will be required to account for overall thyroid iodine metabolism as isotopic equilibrium in man is approached.     

Effects of rapeseed‐press cake glucosinolates and iodine on the performance,the thyroid gland and the liver vitamin a status of pigs

Rapeseed press cake (per kg DM 181 g EE, 341 g CP and 23.3 mmol glucosinolates) was tested in a long‐term experiment with a total of sixty pigs (live weight range 24 to 104 kg). The 3×2 factorial design consisted of three rapeseed press cake levels (no rapeseed press cake ‐ control, 75g or 150g rapeseed press cake per kg diet) each with two iodine dosages (125 or 250 μg supplementary iodine per kg diet). Reduced feed intake and depressed weight gain were found in groups receiving 150 g rapeseed press cake per kg diet, which correspond to 3.2mmol glucosinolates per kg diet. At an inclusion level of 75 g rapeseed‐press cake per kg diet no differences in feed intake and growth intensity were recorded in comparison to the rape feed free control. The rapeseed‐press cake diet increased the weight of thyroid gland and liver and decreased the serum thyroxine (T₄) concentration. Higher iodine dosage increased the serum T₄ concentration of pigs receiving 75 g rapeseed press cake per kg diet ( = 1.6 mmol glucosinolates per kg diet) to the level of the control group and retarded the enlargement of the thyroid gland. Intake of rapeseed products lowered the iodine content of the thyroid gland, however, there was no significant difference between groups given 1.6 and 3.2 mmol glucosinolates per kg diet. The vitamin A content of the whole liver and the vitamin A serum concentration were not influenced by the diets tested. However, rapeseed press cake and the glucosinolates, respectively, decreased the vitamin A concentration per gram liver due to the organ enlargement and the resulting dilution effect.     

Functional state of the thyroid gland following exposure to ultrasound

Changes are described in the content of butanol-extracted iodine in the blood serum and total iodine in thyroid tissue of white rat males under ultrasonic effect of various intensity (0.2, 0.6, 1.0 Watt/cm2) and analysed at different time intervals after ultrasound application. A decrease in total iodine content in thyroid glands (at initial level 0.315 mg%) and an increase of butanol-extracted iodine content in the blood serum were observed in all the experimental groups. The data obtained compared with the earlier found increase of the thyroid hormone content in the serum and thyreotropic hormone at a decreased content of thyroxins in the thyroid gland seem to point to the activation of the thyroid function after the application of ultrasound.     

Effects of Iodine-131 in sheep depending on the content of stable iodine in the diet]

The biological effect of 131I was studied in sheep kept on a diet deficient in stable iodine. An increased capture and accretion of iodine in the thyroid gland and in the whole body were observed. The disturbances in the structure and function of the thyroid gland, liver and haemopoietic organs were more pronounced in the animals kept on the iodine deficient diet.     

The effect of iodide administration on hog thyroid gland and the composition of thyroglobulin and 27-S iodoprotein.

The effect of excess iodide on hog thyroid gland has been examined with regard to the change in the chemical composition of thyroglobulin and in the accumulation of 27-S iodoprotein by the in vivo treatment of hogs with iodide for various lengths of time. The iodine content of thyroglobulin was either unchanged by short term administration of excess iodide, or somewhat lowered. However, the iodine content as well as the total amount of thyroglobulin increased in the glands enlarged by prolonged treatment with iodide. The iodine highest reached 1.17% of the protein on an average. On the other hand, 27-S iodoprotein decreased and finally disappeared after the chronic treatment. Monoiodotyrosine and diiodotyrosine increased in parallel with the increase in the iodine content (0.15 to 1.17%) caused by the iodide treatment, while thyroxine increased but reached a plateau at the level of three residues per mole of thyroglobulin, and no change was observed even in the proteins with the higher iodine content than 0.75%. Proteolytic activity measured by amino acid release from the thyroid protein was depressed by the chronic treatment. On the other hand, the amount of iodocompound released by the autoproteolysis, which may reflect hormone secretion, increased, possibly because of the marked increase in the iodine content of thyroglobulin.