The effect of bromide on the ultrastructure of rat thyrocytes

Velický, J; Titlbach, M; Lojda, Z; Dušková, J; Vobecký, Miloslav; Raška, Ivan

doi:10.1016/s0940-9602(04)80004-9

Cited by 7 publications

(6 citation statements)

References 15 publications

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“…A longer exposure period might have indicated histopathological severity to the thyroid gland and the kidney. A study by Velický et al (2004) noted the adverse effect Br had on the ultra-structure of rat thyroid glands. The administration of 10, 50 and 100 mg Br/L for 16 or 60 days resulted in marked hypertrophy and hyperplasia of the thyroid gland, micro follicular rearrangement and lower colloid volume.…”

Section: Discussionmentioning

confidence: 99%

“…The biggest influence is on the production of thyroid gland hormones; the thyroid glands of rats that received high dietary Br increased significantly (Rauws and Van Logten, 1975). The goitrogenic effect of Br is further supported by Velický et al (2004) who recorded marked changes in the morphology of the thyroid gland and reduced iodide accumulation in the thyroid gland, as well as the skin in rats fed a diet containing a high concentration of Br. Hellerstein et al (1960) reported that species differences of Br concentrations in tissues were small and that Br does not accumulate in a particular organ or tissue.…”

Section: Introductionmentioning

confidence: 86%

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Iodine as an alleviator of bromine toxicity in thyroid, liver and kidney of broiler chickens

Toit

Casey

2012

Livestock Science

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The study pursued the hypothesis that bromine (Br) in drinking water at levels > 0.01 mg Br/L may have detrimental effects on the liver, kidneys and thyroid and the thyroid hormones T 3 and T 4 and that iodine (I) may alleviate the potential hazardous effect of Br. The research was done with mixed Ross broiler chickens over a 42-day post-hatch growth period. The trial design was six treatments, T1: 0 mg Br/L and 0 mg I/L; T2: 1 mg Br/L and 0 mg I/L; T3: 3 mg Br/L and 0 mg I/L; T4: 0 mg Br/L and 0.7 mg I/L; T5: 1 mg Br/L and 0.7 mg I/L; and T6: 3 mg Br/L and 0.7 mg I/L delivered via drinking water and three replicates per treatment with 30 birds per replicate. The effect of Br on T 3 and T 4 levels overall was nonsignificant, but T 3 and T 4 levels decreased between Weeks 4 and 6 with a significant effect at Week 6 on T 3 . Br had an overall effect on the thyroid gland (P = 0.0457), liver (P = 0.0025) and kidney (P = 0.0032), and had accumulated in these three organs. Histopathological assessment showed explicit damage to the livers that received the Br treatments. Iodine (0.07 mg/L) ameliorated the negative effects of high Br (3 mg/L Br) concentration and ingestion.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 86%

Iodine as an alleviator of bromine toxicity in thyroid, liver and kidney of broiler chickens

Toit

Casey

2012

Livestock Science

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“…Changes in goitrogenic cellular amounts, identified on the basis of light and electron microscopic evaluation of thyroid tissue, were reported in rats receiving 10, 50, 100, 200, and 400 mg of bromide (as KBr) for various durations. 48,[80][81][82] At very high doses (19,200 mg of NaBr/kg of feed [8,727.3 mg/lb of feed]), histologic changes in rat thyroid tissue (eg, increased number of smaller follicles, higher amounts of follicular epithelium, decreased amounts of colloid, and a more granular appearance) and reduced thyroxine concentration indicated decreased thyroid activity. 43 A statistically significant decrease in total thyroxine concentration was also identified in animals treated in another study 45 with similar design at doses ≥ 4,800 mg/kg.…”

Section: Discussionmentioning

confidence: 99%

“…Sixty publications were classified as providing supportive evidence, such as descriptive information that supported ADEs documented in the primary evidence publications. These publications involved dogs, 13,17,20,61-74,b,c cats, 21 rabbits, 22,61 rats, [75][76][77][78][79][80][81][82] mice, 83 cattle, 84 goats, 84,85 horses, 84,86 and humans. 5,7,23,24, These publications described important ADEs, but were limited in their ability to clearly attribute ADEs to bromide administration.…”

Section: Ratsmentioning

confidence: 99%

A systematic review of the safety of potassium bromide in dogs

Baird-Heinz¹,

Schoick²,

Pelsor³

et al. 2012

javma

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Results suggested that potassium bromide is not an appropriate choice for treatment of every dog with seizures and that practitioners should tailor therapeutic regimens and clinical monitoring to each dog. Abrupt dietary changes or fluid therapy may compromise seizure control or increase the likelihood of adverse events. Availability of an appropriately labeled, approved potassium bromide product could provide better assurance for veterinarians and their clients of the quality, safety, and effectiveness of the product for veterinary use.

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“…Although studies are available in rats (Loeber et al, 1983;Velicky et al, 2004) and fish (Wester and Canton, 1986) indicating conserved responses of the thyroid to bromide exposure across vertebrates, no Critical Reviews in Toxicology Downloaded from informahealthcare.com by University of Texas at Austin on 09/18/13…”

Section: Inhibitors Of Iodide Uptakementioning

confidence: 99%

Screening chemicals for thyroid-disrupting activity: A critical comparison of mammalian and amphibian models

Pickford

2010

Critical Reviews in Toxicology

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In order to minimize risks to human and environmental health, chemical safety assessment programs are being reinforced with toxicity tests more specifically designed for detecting endocrine disrupters. This includes the necessity to detect thyroid-disrupting chemicals, which may operate through a variety of modes of action, and have potential to impair neurological development in humans, with resulting deficits of individual and social potential. Mindful of these concerns, the consensus favors in vivo models for both hazard characterization (testing) and hazard identification (screening) steps, in order to minimize false negatives. Owing to its obligate dependence on thyroid hormones, it has been proposed that amphibian metamorphosis be used as a generalized vertebrate model for thyroid function in screening batteries for detection of thyroid disrupters. However, it seems unlikely that such an assay would ever fully replace in vivo mammalian assays currently being validated for human health risk assessment: in its current form the amphibian metamorphosis screening assay would not provide capacity for reliably detecting other modes of endocrine-disrupting activity. Conversely, several candidate mammalian screening assays appear to offer robust capacity to detect a variety of modes of endocrine-disrupting activity, including thyroid activity. To assess whether omission of an amphibian metamorphosis assay from an in vivo screening battery would generate false negatives, the response of amphibian and mammalian assays to a variety known thyroid disrupters, as reported in peer-reviewed literature or government agency reports, was critically reviewed. Of the chemicals investigated from the literature selected (41), more had been tested in mammalian studies with thyroid-relevant endpoints (32) than in amphibian assays with appropriate windows of exposure and developmental endpoints (27). One chemical (methoxychlor) was reported to exhibit thyroid activity in an appropriate amphibian assay in the absence of corresponding activity in a suitable mammalian assay, whereas none of the chemicals surveyed were reported as thyroid active in mammalian assays but reported as negative in an appropriate amphibian assay. Given the need for one or more in vivo mammalian assays for screening chemicals for detecting (anti-)estrogenic/(anti-)androgenic activity and effects on steroidogenesis, inclusion of an in vivo amphibian assay specifically to detect thyroid disrupters would likely be as an addition to these mammalian assays. As there is little convincing evidence that an amphibian screening assay would detect significant numbers of thyroid-active chemicals not picked up by mammalian assays, the routine use of an amphibian metamorphosis assay at screening level could introduce unnecessary and unjustified redundancy into chemical safety assessment programs, when there is pressure to reduce animal use in toxicity testing.

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The effect of bromide on the ultrastructure of rat thyrocytes

Cited by 7 publications

References 15 publications

Iodine as an alleviator of bromine toxicity in thyroid, liver and kidney of broiler chickens

Iodine as an alleviator of bromine toxicity in thyroid, liver and kidney of broiler chickens

A systematic review of the safety of potassium bromide in dogs

Screening chemicals for thyroid-disrupting activity: A critical comparison of mammalian and amphibian models

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