Abstract
Effects on Ca++ translocation and [Ca++]i were studied in dog thyroïd cell monolayers using both 45Ca++ efflux and the indicator quin-2. Carbamylcholine, a non hydrolysable analog of acetylcholine, through muscarinic receptors, and to a lesser extent TRH and PGF2 alpha increased both these parameters. [Ca++]i increased by 171, 100 and 75% respectively over a basal level of 66 +/- 17 nM (mean +/- SD). The response to carbamylcholine was biphasic. A transient increase in [Ca++]i was followed by a more sustained phase where the [Ca++]i was slightly higher than the basal level. Only the first phase was insensitive to extracellular Ca++ depletion. This phase is probably due to a release of Ca++ from an intracellular store. NaF also induced a sustained rise in [Ca++]i dependent on extracellular Ca++ and affected 45Ca++ efflux. Our data provide direct evidence of an implication of intracellular Ca++ in the response of dog thyroïd cells to all these agents.
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Fluoride-induced thyroid dysfunction in rats: roles of dietary protein and calcium level.
To assess the roles of dietary protein (Pr) and calcium (Ca) level associated with excessive fluoride (F) intake and the impact of dietary Pr, Ca, and F on thyroid function, 144 30-day-old Wistar albino rats were randomly allotted to six groups of 24 (female:male = 1:1). The six groups were
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Effect of sodium fluoride on the thyroid follicular cells and the amelioration by calcium supplementation in albino rats: A Light And An Electron Microscopic Study
Sodium fluoride was the first fluoride compound used in the fluoridation of drinking water and it is still commonly used for that purpose to prevent dental caries. It exerts toxic effects on many soft tissues and organs. The thyroid gland has a strong capacity for absorbing and accumulating fluoride. Objective: The
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Effects of excess fluoride and iodide on thyroid function and morphology
Exposure to high levels of iodide in Cangzhou, Shandong Province, China has been associated with increased incidence of thyroid disease; however, whether fluoride can affect the thyroid remains controversial. To investigate the effects of excess fluoride, we evaluated thyroid gland structure and function in rats exposed to fluoride and iodide,
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Effects of protein and calcium supplementation on bone metabolism and thyroid function in protein and calcium deficient rabbits exposed to fluoride
This study was conducted to determine whether feeding a diet containing excess crude protein (CP) or calcium (Ca) for up to 120 days can ameliorate the effects of fluoride (F) intake on bone health and thyroid function observed in rabbits fed a CP- and Ca-deficient diet. Treatment with F increased serum bone Gla
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Role of endoplasmic reticulum stress-induced apoptosis in rat thyroid toxicity caused by excess fluoride and/or iodide
Excess fluoride and iodide coexist in drinking water in many regions, but few studies have investigated the single or interactive effects on thyroid in vivo. In our study, Wistar rats were exposed to excess fluoride and/or iodide through drinking water for 2 or 8 months. The structure and function of
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Fluoride Exposure Aggravates the Impact of Iodine Deficiency
A consistent body of animal and human research shows that fluoride exposure worsens the impact of an iodine deficiency. Iodine is the basic building block of the T3 and T4 hormones and thus an adequate iodine intake is essential for the proper functioning of the thyroid gland. When iodine intake is inadequate during infancy and
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Fluoride Aggravates Thyroid Damage Caused by Excess Iodine Intake
Chinese researchers have found that the combination of excess fluoride with excess iodine caused greater reductions in IQ, or greater increases in goitre than either scenario by itself.
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Fluoride & Goiter
Goitre (aka goiter) is an enlargement of the thyroid gland that in some cases can produce visible swelling in the neck. The main cause of goitre is iodine deficiency. Goitre can also be caused by other things, including hypothyroidism and substances that cause goitre (goitrogens). Since as far back as the
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Mikhailets (1996): Functional state of thyroid under extended exposure to fluorides
Abnormalities in the thyroid function characterized by a decreased iodine absorption function of the thyroid, a low level T3 syndrome, and a slight increase of the TSH level are observed in cases of chronic fluorine intoxication in the industrial workers.
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Fluoride, Water Hardness, and Endemic Goitre
Variations in goitre prevalence were found to correlate closely with the fluoride content (p=0-74; P<0-01) and with the hardness (p=0.77; P<0-01) of the water in each village. The effects of fluoride and water hardness seem to be independent.
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