Abstract
Sodium fluoride (CAS 7681-49-4) 5-20 micromol/L in the extracellular space inhibited insulin secretion by isolated Langerhans islets stimulated with glucose. Insulin secretion followed a negative exponential function. This phenomenon is rapidly reversible. Perfusion of pancreatic tissue (rat) in vivo with stimulatory levels of glucose revealed that 20 micromol/L fluoride in the perfusion fluid inhibited the initial and sustained phases of insulin secretion to 15% of that of controls. The stimulatory effects of the ionophore A23187, phorbol-ester and forskolin on the secretion of insulin of isolated rat Langerhans islets in vitro were inhibited by 20 micromol/L fluoride. The results suggested that fluoride affects some stage of insulin secretion situated below the cascade of events that include the participation of calmodulin, protein-kinase C and cyclic AMP.
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Changes in the metabolism of glucose and calcium following a single large dose of fluoride to rats
Serum glucose level was elevated immediately after ip administration of a single large dose of fluoride (NaF 35 mg/kg) to rats. The elevation of serum glucose was markedly suppressed by adrenalectomy, dibenamine or propranolol, but not by thyroid-parathyroidectomy. Elevation of serum glucose was found to be associated with enhancement of
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The effects of fluoridated water on rat urine and tissue cAMP levels
Male Wistar rats were fed a fluoride deficient diet (less than 0.5 parts/10(6) F), and either distilled water or fluoridated water (1.0 parts/10(6)). By week 3, the control group had urinary excretions of 106 +/- 5 nmol cAMP/day (mean +/- SEM) whereas the experimental group excreted 129 +/- 6 nmol
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Predominant contribution of the G protein-mediated mechanism to NaF-induced vascular contractions in diabetic rats: association with an increased level of G(qalpha) expression.
The purpose of this study was to determine the mechanism responsible for alterations in NaF-induced contractions of blood vessels from streptozotocin-induced diabetic rats. In the presence of AlCl(3), NaF (>/=7.5 mM) produced significantly greater contractions in diabetic aorta and mesenteric artery compared with age-matched controls. Pretreatment with 1 microM nifedipine
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Fluoride stimulates in vitro vascular prostacyclin synthesis: interrelationship of G proteins and protein kinase C
The role of G proteins in mediating adrenoceptor-prostacyclin synthesis coupling was investigated using the G protein activator, sodium fluoride. Sodium fluoride (NaF) stimulated in vitro rat aortic prostacyclin (PGI2) synthesis (EC50 = 5 x 10(-3) mol.l-1), an action inhibited completely by the presence of EDTA (10(-2) mol.l-1). The NaF-PGI2 dose-response
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Aluminum: a requirement for activation of the regulatory component of adenylate cyclase by fluoride
Activation of the purified guanine nucleotide-binding regulatory component (G/F) of adenylate cyclase by F- requires the presence of Mg2+ and another factor. This factor, which contaminates commercial preparations of various nucleotides and disposable glass test tubes, has been identified as Al3+. In the presence of 10 mM Mg2+ and 5
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Fluoride & Impaired Glucose Tolerance
The proper regulation of blood glucose levels is essential to good health. When the body's ability to regulate blood glucose levels falters, as occurs in diabetes mellitus, chronic elevated glucose levels (hyperglycemia) can lead to serious complications. These consequences include damage to the kidneys, nervous system, cardiovascular system, retina, legs
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Fluoridated Water Causes Severe Dental Fluorosis in Children with Diabetes Insipidus
This section on Diabetes includes: • Fluoride & Impaired Glucose Tolerance • Fluoride & Insulin • Fluoride Sensitivity Among Diabetics • Fluoridated Water Causes Severe Dental Fluorosis in Children with Diabetes Insipidus • NRC (2006): Fluoride’s Effect on Glucose Metabolism Excessive exposure to fluoride causes a defect of the tooth enamel known as dental fluorosis. In
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Fluoride & Insulin
Insulin is a hormone produced by the pancreas that is responsible for maintaining appropriate levels of glucose in the blood. Insulin allows the body’s cells to take up glucose from the blood, and either use it as an energy source or store it as glycogen. Blood glucose levels in diabetics
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Fluoride Sensitivity Among Diabetics
This section on Diabetes includes: • Fluoride & Impaired Glucose Tolerance • Fluoride & Insulin • Fluoride Sensitivity Among Diabetics • Fluoridated Water Causes Severe Dental Fluorosis in Children with Diabetes Insipidus • NRC (2006): Fluoride’s Effect on Glucose Metabolism “The present study showed that aortae and mesenteric arteries from streptozotocin-induced diabetic rats exhibited greater contractions
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NRC (2006): Fluoride's Effect on Glucose Metabolism
This section on Diabetes includes: • Fluoride & Impaired Glucose Tolerance • Fluoride & Insulin • Fluoride Sensitivity Among Diabetics • Fluoridated Water Causes Severe Dental Fluorosis in Children with Diabetes Insipidus • NRC (2006): Fluoride’s Effect on Glucose Metabolism The following discussion is from pages 258-260 of the NRC’s report’s “Fluoride in Drinking Water: A Scientific
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