Thyroid extract

Several drugs are known to affect calcium metabolism and to Induce calcium loss (42). Amongst these are the use of glucocorticoids and thyroid extract. The use of both of these drugs can lead to the development of osteoporosis. It Is less well known that several other... 

In 1858 Schiff removed the thyroid gland from animals and found they could not survive. From his, and later, Horsley s, experiments and from the clinical observations it was concluded that the effects of removal or damage to the thyroid were due to a loss of its internal secretions. Confirmation of this came when patients with myxoedema were successfully treated by thyroid extracts or even by eating thyroid tissue. 

Thyroid extract/thyroxine Hormone Thyroid gland... 

Gerard P, Malvaux P, De Visscher M. Accidental poisoning with thyroid extract treated by exchange transfusion. Arch Dis Child 1972 47(256) 981-982. 

The first diet pills (e.g., thyroid extracts) are marketed in United States. 

Attitudes about weight had changed somewhat by 1893 when the first diet pill was marketed. The pill was a thyroid extract sold under names like Frank J. Kellogg s Safe Fat Reducer. People lost weight. However, there were dangerous side effects for people who did not have a hypothyroid condition. Hypothyroidism is a glandular condition characterized by an impaired rate of metabolism. 

The use of desiccated thyroid rather than synthetic preparations is never justified, since the disadvantages of protein antigenicity, product instability, variable hormone concentrations, and difficulty in laboratory monitoring far outweigh the advantage of low cost. Significant amounts of T3 found in some thyroid extracts and liotrix may produce significant elevations in T3 levels and toxicity. Equivalent doses are 100 mg (1.5 g) of desiccated thyroid, 100 Mg of levothyroxine, and 37.5 ug of liothyronine. 

Perry WF (1951) A method for measuring thyroid hormone secretion in the rat with its application to the bioassay of thyroid extracts. Endocrinology 48 643-650 Reineke EP, Turner CW (1950) Thyroidal substances. In Em-mens CW (ed) Hormone Assay, Chapter XIX. Academic Press Inc., New York, pp 489-511 Turner CW, Premachandra BN (1962) Thyroidal substances. In Dorfman RI (ed) Methods in Hormone Research, Vol II, Chapter 10. Academic Press, New York and London, pp 385-411... 

Anesthetics Antihistamines Antiparkinsonian agents Barbiturates Benzodiazepines Chloral hydrate Hypoglycemic agents Opiate analgesics Thyroid extract Tricyclic antidepressants... 

When diuretics are abused it is mostly in the course of a misguided attempt to lose weight in the past, various slimming remedies offered for sale outside normal trading channels have been found to contain diuretics, sometimes with components such as thyroid extract. The unnecessary use of diuretics by a healthy individual, perhaps in excessive doses, can lead to dehydration, hypokalemia, and hypotension when furosemide is abused, even tetany can occur because of hypocalcemia (126). The weight loss achieved by using diuretics in this way is purely due to dehydration and will soon be annulled by extra fluid intake. 

There is very little published research looking at blood T4 levels in horses on thyroid supplementation. A single dose of 20 j,g/kg T4 will maintain blood levels in the reference range for 24 h (Bayly et al 1996). There are several other forms of T4 available for the treatment of horses, lodinated casein, orally at 5.0g/day, is not readily available currently but has been recommended in the past (Sojka 1995). Concentrated bovine thyroid extract at a dosage of 10.5g/day has been reported to return thyroid hormone serum concentrations to normal (Sojka 1995). 

See also Endocrine System Levothyroxine Thyroid Extract. 

Thyroid extract is used in the treatment of hypothyroidism, myxedema, and cretinism. It is also used as a diagnostic agent and for suppression of pituitary thyroid-stimulating hormone. Synthetic derivatives are preferred because of uniform potency. 

Thyroid extract is partially absorbed from the gastrointestinal tract. Up to 79% of a therapeutic dose is absorbed. Approximately 99% is protein bound. Thyroid extract contains both levothyroxine (T4) and liothyronine (T3). T4 is deiodinated in the liver, kidney, and tissues to form active T3 and inactive T2. The half-life of T4 is 5.3-9.4 days. T3 has a half-life of 2.5 days. 

Animals that ingest thyroid extract are at risk for thyroid toxicity. Signs of toxicity include vomiting, diarrhea, tachycardia, tachypnea, a decreased level of consciousness, and restlessness. Animal preparations frequently have higher concentrations that human preparations do. 

Ingestion of small amounts of thyroid extract produces few symptoms, if any. Symptoms of thyroid toxicity include increased heart rate, nausea, vomiting, diarrhea, restlessness, and fever. The development of thyrotoxicosis with acute exposure is rare except in very large overdoses (grams of thyroid extract containing several milligrams of T3 and/or T4). 

Thyroid extract has been used in veterinary practice. Current practice involves synthetic levothyroxine. 

Chronic overdosing is more likely to cause thyrotoxicosis than an acute overdose. Thyrotoxicosis should be suspected in patients exhibiting tachycardia, cardiac arrhythmias, hypertension, tremors, and seizures. Coma and circulatory collapse can be seen in severe cases of thyrotoxicosis. This is especially dangerous in patients with cardiac conditions. Deaths have also occurred in healthy adults that have used thyroid extract to lose weight. 

Thyroid Extract, Pages 186-187, Greene Shepherd SummaryPlus Full Text + Links PDF (54 K)... 

Inevitably, the infrequent isolation of true pathogens, such as Salmonella spp. and the reporting of associated infections following the use of products contaminated with these organisms (tablets, pancreatin and thyroid extract), have attracted considerable attention. More often, the isolation of common saprophytic and non-fastidious opportunist contaminants with limited pathogenicity to healthy individuals has presented a significant challenge to compromised patients. 

Calcium absorption is reduced by high pH complex-ing agents such as oxalate, phytate, free fatty acids, and phosphate and shortened transit times. These factors are probably of clinical importance only when associated with vitamin D deficiency, marginal calcium intake, or malabsorption disorders. Absorption is also reduced by increased intake of protein, fat, and plant fiber increasing age stress chronic alcoholism immobilization (e.g., prolonged hospitalization) and drugs such as tetracycline, thyroid extract, diuretics, and aluminum-containing antacids. 

There are now numerous reports confirming that thyroid extracts from many animal species are effective in lowering plasma calcium levels. Foster et al. (F4) prepared a simple acid extract of goat thyroid, which. 

As was mentioned earlier, there appears to be considerable species variation in the secretion of thyrocalcitonin, and likewise there are reports of species variations in sensitivity to exogenous thyrocalcitonin preparations. Care et al. (C8) found sheep to be considerably less responsive to exogenous sheep thyrocalcitonin than pigs to porcine thyrocalcitonin. Smith et al. (S2) were unable to demonstrate hypocalcemic activity in human thyroid extracts injected into monkeys or rats, but found the mouse to be responsive. On the other hand, Milhaud et al. (M12) demonstrated hypocalcemic activity in human thyroid extracts in the rat and monkey, although these responses were obtained only after injecting much larger doses than would have been required had porcine... 

Using intravenous infusions, Baghdiantz et al. (Bl) obtained a 10% fall in plasma calcium in the rat with relatively crude salt-fractionated pig thyroid extract containing 8 fig of protein nitrogen. The purest preparation reported by these workers appears to have been about 20 times more potent, i.e., 0.4 fig of protein nitrogen produced an approximately 10% fall. 

Tashjian, A. H., and Munson, P. L., Antibodies to porcine thjfrocalcitonin Effects on the hypocalcaemic activity of calf, rat and monkey thyroid extracts. Endocrinology 77, 520-528 (1965). 

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