PFPC Fluoride Education Project

Having studied the moderating action of fluorides on nutrition, G. wondered whether endemic goiter might not be due to the action of some fluorinated compound contained in goitrogenic waters.

A first series of experiments undertaken on rabbits did not give him convincing results. He was more successful with the white rat, and these are the results he reports today.

The control animals were fed bread, milk, water, and cooked potatoes. The same paste was given to the experimental animals, into which a 2% solution of sodium fluoride was incorporated, calculating the dose so as to make each animal take about 3 milligrams per day. After 6 to 8 months, the subject died or was sacrificed. Now, in all the experimental animals, G. noted very clear thyroid hypertrophy: the volume of the gland was increased fivefold, and the histological lesions observed were those of parenchymatous goiter, comparable to colloid goiter. In the kidneys, lesions of epithelial nephritis were noted.

In addition, G. was able to observe, in rats subjected from birth to the action of fluorine, developmental arrest and signs of intoxication analogous to those observed in thyroid cretinism. These accidents stopped very quickly as soon as the animal was removed from the fluorinated environment.

Fluorides taken daily stop or diminish the growth of young rabbits, and a dose of 0.20 g to 0.30 g sodium fluoride causes, after a few minutes, a fall in rectal temperature in the rabbit, which can reach several degrees and can last for many hours. In the white rat, daily ingestion of 2 to 3 milligrams of sodium fluoride, for 6 to 8 months, produces hypertrophy of the thyroid gland with histological lesions similar to those of endemic goiter.

On the basis of these experiments, G. tried to treat hyperthyroidism with fluorine. Very few patients tolerate sodium fluoride by ingestion beyond a few days, so they prefer intravenous injections of 2 to 6 cc of a 2.5% solution. After a series of 30 to 40 daily injections, treatment is suspended for 15 to 20 days, then resumed and continued in this way for 10 to 12 months. Five to ten minutes after the injection, many patients experience quite intense pain with a feeling of cramping in the lumbar region or in the abdomen.

The therapeutic action appears slowly and gradually. The nervous symptoms are the first to give way, then sleep returns to normal and the tachycardia begins to disappear. Basal metabolism and accelerated erythrosedimentation slowly diminish until they return almost completely to normal. The goiter decreases greatly in volume and may disappear completely when it is especially vascularized or congestive. Exophthalmos may decrease, but sometimes it remains unchanged. Six observations, including recovery maintained for 6 months to 3 years, show the effectiveness of this treatment, which G. would have applied in about fifty cases of Basedow’s disease.

Robert Clément

According to investigations by Répin, Bircher, Houssay, and others, white rats are very well suited for producing goiter through the continued administration, over several months, of goiter-producing water. According to the author’s experiments, white rats that were fed 2-3 mg sodium fluoride daily for 6-8 months showed enlargement of the thyroid gland, that is, a goiter, about 5-6 times as large as the normal thyroid gland, with the histological characteristics of parenchymatous or colloid goiter. In addition, epithelial or tubular nephritis was observed. The clinical picture resembled thyroid cretinism. Most of the animals fed 3 mg died after 6-8 months. The diet consisted of white bread, milk, and water, occasionally also boiled potatoes. Compared with normal animals, the fluorine animals lagged behind in growth, especially during the first 2 months. With larger doses, more severe signs of poisoning occurred, such as subcutaneous hemorrhages, severe emaciation, gait disturbances, and lethargy. (Flury.)