Abstract
Five healthy subjects were each given fluoride 3.0 mg (F) as sodium fluoride tablets on two occasions – during production of acid urine, induced by giving NH4Cl, and during production of alkaline urine obtained by giving NaHCO3. Frequent plasma and urine samples were taken up to 12 h and were analyzed with a F- sensitive electrode. Control experiments without F administrations were also performed to permit calculation of net F concentration in plasma and urine. The urine F excretion was lower during acid than alkaline diuresis. Pharmacokinetic analysis of the net plasma F concentrations showed that the apparent plasma half-life of F was longer when urine was acid (4.3 +/- 0.6h: SD; n = 5) than when it was alkaline (2.4 +/- 0.4h). This could be explained by changes in the renal clearance of F, which was always lower with an acid (61.5 +/- 8.1 ml/min) than an alkaline (97.8 +/- 10.4 ml/min) urine. The apparent extra-renal clearance, which mainly represents clearance to the bone-pool, was also significantly higher during production of alkaline (109.2 +/- 20.2 ml/min) than of acid (86.3 +/- 21.3 ml/min) urine. It is suggested, that increased reabsorption of non-ionic hydrogen fluoride (HF) is responsible for the decreased renal clearance during acidic conditions.
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Fluoride metabolism
Knowledge of all aspects of fluoride metabolism is essential for comprehending the biological effects of this ion in humans as well as to drive the prevention (and treatment) of fluoride toxicity. Several aspects of fluoride metabolism - including gastric absorption, distribution and renal excretion - are pH-dependent because the coefficient
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Intake and metabolism of fluoride
The purpose of this paper is to discuss the major factors that determine the body burden of inorganic fluoride. Fluoride intake 25 or more years ago was determined mainly by measurement of the concentration of the ion in the drinking water supply. This is not necessarily true today because of
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Plasma and developing enamel fluoride concentrations during chronic acid-base disturbances
Mild acid-base disturbances were induced in rats for 30 days. These disturbances did not affect % ash of maxillary incisors or % P of the developing enamel from mandibular incisors. Total fluoride intake (food and water) among groups drinking fluoride-free water was constant. Nevertheless, average plasma and developing enamel fluroide
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Fluoride renal clearance: a pH-dependent event
The renal clearance of fluoride (CF) was studied in pentobarbital-anesthetized rats. Urine flow rate and chloride clearance, previously thought to be the main determinants of CF, were readily dissociated from CF. Neither the clearance of sodium nor the excretion of potassium correlated consistently with CF. In experiments designed to manipulate
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Sodium Fluoride F 18: Summary of Use during Lactation.
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