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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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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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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Hyperplastic nodules of thyroid parafollicular cells (C cells) in rats induced by prolonged low dose ingestion of NaF
In rats which received drinking water containing 0, 3, 6, 12, 25 ppm NaF (F-) for 20 months, hyperplastic nodules, consisting of thyroid parafollicular cells (C cells) appeared in all F- groups, particularly in those which received 12 and 25 ppm. By immuno-histochemistry and electron microscopy, both calcitonin and characteristic
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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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Effects of fluoride on metamorphosis, thyroid and skeletal development in Bufo gargarizans tadpoles
This study examined the effects of chronic fluoride exposure on metamorphosis, thyroid and skeletal development in tadpoles of Chinese Toad, Bufo gargarizans. The tadpoles were exposed to fluoride concentrations either at 0, 1, 5, 10, or at 50 mg L(-1) from Gosner stage 26 to Gosner stage 42. Body weight,
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The Relationship Between Fluoride Exposure & Goitre in South Africa
As a general rule simple goitre, irrespective of the cause, can be very, or fairly, satisfactorily combated by an adequate increase in man's daily iodine intake, except when the enlargement of the gland is due to the ingestion of excessive amounts of fluorine. The only correct solution to fluorine-induced endemic goitre is the removal of this element from the drinking water.
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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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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's Impact on Thyroid Hormones
Up through the 1950s, doctors in Europe and South America prescribed fluoride for this purpose in patients with hyperthyroidism. (Merck Index 1968). Fluoride was selected as a thyroid suppressant based on findings dating back to the mid-19th century that fluoride is a goitrogen (a substance that can cause goiter). When used as
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Fluorine in the Aetiology of Endemic Goitre
The distribution of endemic goitre in the Punjab and in England is related to the geological distribution of fluorine and to the distribution of human dental fluorosis (mottled enamel). Inquiry showed the presence of dental fluorosis among school-children in two areas of Somerset where two previous observers had recorded a high incidence of goitre, and the absence of dental fluorosis in an adjoining area selected as control where endemic goitre was absent.
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