Thyroid extract, effect

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. 

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. 

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. 

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). 

Thyroxine is one of the few hormones for which unequivocal effects on isolated biochemical systems can be observed in particular, it has been shown that thyroxine at high concentrations has a direct effect on mitochondrial oxidation. Tissues from animals which have been injected with thyroid extracts or purified thyroxine show a raised oxygen consumption, particularly in liver and muscle. Similarly the addition of thyroxine to tissue slices of the same organs results in increased oxidation. Thyroxine seems to be especially trapped by the mitochondria, where it stimulates the... 

Another factor complicating the interpretation of plasma tocopherol levels is the question of protein carriers involved in transport of vitamin E in the blood. In circumstances where plasma cholesterol is high, plasma tocopherol also tends to be elevated (Darby et al., 1949). Our experience with the effect of discontinuation of thyroid extract on plasma tocopherol of five cretins is shown in Table III. It can be seen that over a 10-week period without thyroid the vitamin E blood level rose in two of four patients and by 18 weeks the level rose in the other two. There is certainly... 

In 1914, Kendall, a scientist at the Mayo Clinic in Minnesota, crystallized thyroxin, one of the thyroid hormones. The chemical structure of thyroxin wtis described in 1927 by Harrington and Barger, British university scientists. Harrington synthesized thyroxin, thereby paving the way for a more effective therapeutic agent than thyroid extracts which were variable in biological potency. 

An alternative therapeutic approach to osteoporosis is through the use of calcitonin (798), a peptide hormone containing 32 amino acids (the sequence is species dependent) secreted by the thyroid gland, which stimulates the production of new bone. Synthetic calcitonins corresponding to human, eel, and salmon variants, and natural calcitonin extracted from pig thyroid, are all used in medicine - they have slightly different efficacies, side effects, and tolerance levels (799). 

Gaitan E, Cooksey RC, Legan J, Cruse JM, Lindsay RH, Hill J (1993) Antithyroid and goitrogenic effects of coal-water extracts from iodine-sufficient goiter areas. Thyroid 3 49-53... 

OE219 Al-Quarawi, A. A., M. A. Al-Damegh, and S. A. El-Mougy. Effect of freeze-dried extract of Olea europaea on the pituitary-thyroid axis in rats. Phytother Res 2002 16(3) 286-287. 

The earlier evidence for a second parathyroid hormone (calcitonin) cannot be said to have been either satisfactorily established or finally disproved. Conflicting reports on the systemic effects of separate perfusions of thyroid and of parathyroid glands, and on the presence or otherwise of consistent biphasic effects on plasma calcium when extracts of the parathyroid gland are injected, have contributed to the atmosphere of uncertainty. There are, however, some observations that cannot be readily explained solely on the basis of a thyroid origin for the hypocalcemic principle, notably the effects of cross-transfusion of parathyroid venous plasma in the sheep and the impaired tolerance to infused calcium that follows parathyroidectomy without thyroidectomy. 

With the possible exception of the effects of pituitary extracts in the rabbit, there is no evidence that tissues other than the thyroid and parathyroid glands can store or secrete calcium-regulating hormones. 

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