posted August 02, 2000 06:14 PM         

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Just wondering how effective it is and if there's a possibility of fucking up your thyroid with it, as mentioned about T3

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~~~ ajc1977 ~~~
Visit my member website at http://profiles.elitefitness.com

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posted August 02, 2000 06:34 PM         

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Anyone had any luck with it.

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posted August 02, 2000 06:42 PM            

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I'll scan in some info from a clinical pharmacology program...

Description: Each levothyroxine sodium, USP tablet contains synthetic crystalline levothyroxine sodium (L-thyroxine). L-thyroxine is the principal hormone secreted by the normal thyroid gland. Chemically, L-thyroxine is designated as L-tyrosine, O-(4-hydroxy-3, 5-diiodophenyl) - 3,5-diiodo -, monosodium salt, hydrate.

Warning: Thyroid hormones, either alone or together with other therapeutic agents, should not be used for the treatment of obesity. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.

Clinical Pharmacology: The synthesis and secretion of the major thyroid hormones L-thyroxine (T4) and L-triiodothyronine (T3) from the normally functioning thyroid gland are regulated by complex feedback mechanisms of the hypothalamic-pituitary-thyroid axis. The thyroid gland is stimulated to secrete thyroid hormones by the action of thyrotropin (thyroid stimulating hormone, TSH) which is produced in the anterior pituitary gland. TSH secretion is in turn controlled by thyrotropin-releasing hormone (TRH) produced in the hypothalamus, circulating thyroid hormones, and possibly other mechanisms. Thyroid hormones circulating in the blood act as feedback inhibitors of both TSH and TRH secretion. Thus, when serum concentrations of T3 and T4 are increased, secretion of TSH and TRH is increased Administration of exogenous thyroid hormones to euthyroid individuals results in suppression of endogenous thyroid hormone secretion.
The mechanisms by which thyroid hormones exert their physiologic actions have not been completely elucidated. T4 and T3 are transported into cells by passive and active mechanisms. T3 in cell cytoplasm and T3 generated from T4 within the cell diffuse into the nucleus and bind to thyroid receptor proteins, which appear to be primarily attached to DNA. Receptor binding leads to activation or repression of DNA transcription, thereby altering the amounts of mRNA and resultant proteins. Changes in protein concentrations are responsible for the metabolic changes observed in organs and tissues.
Thyroid hormones enhance oxygen consumption of most body tissues and increase the basal metabolic rate and metabolism of carbohydrates, lipids, and proteins. Thus, they exert a profound influence on every organ system and are of particular importance in the development of the central nervous system. Thyroid hormones also appear to have direct effects on tissues, such as increased myocardial contractility and decreased systemic vascular resistance.
The physiologic effects of thyroid hormones are produced primarily by T3, a large portion of which is derived from the from the deiodination of T4 in peripheral tissues. About 70 to 90 percent of peripheral T3 is produced by monodeoidination of T4 at the 5' position (outer ring). Peripheral monodeiodination of T4 at the 5 position (inner ring) results in the formation of reverse triiodothyronine (rT3), which is calorigenically inactive.

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posted August 02, 2000 06:45 PM            

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E-toon, you are just one big encyclopedia of info! Peace, Mav

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posted August 02, 2000 06:55 PM            

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Bump for e-toon!!!!!!!!!!
Stay away from from anything that screws with the tyroid. Its not worth it!!!!!!

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posted August 02, 2000 07:14 PM            

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First, take enough of anything and it can be dangerous. With that out of the way, here we go:

Thyroid hormone is usually prescribed as pure synthetic thyroxine (T4, aka Synthroid). Desiccated (dried and powdered) animal thyroid, once the most common form of thyroid therapy, is rarely prescribed today because it also contains triiodothyronine (T3), a rapidly acting thyroid hormone which produces more variable blood levels than pure thyroxine preparations. It also may vary in potency from batch to batch, because it comes from animal thyroid glands, which can vary in their thyroid hormone content. Most endocrinologists switch patients who are taking desiccated thyroid to synthetic thyroxine, which is purer and has a constant level of potency. There is no evidence that desiccated thyroid, a biological preparation, has any advantage over synthetic thyroxine.

Thyroxine and triiodothyronine are produced in the thyroid gland by the iodination and coupling of the amino acid tyrosine. Thyroxine contains 4 iodine atoms and is formed by the coupling of 2 molecules of diiodotyrosine. Triiodothyronine contains 3 iodine atoms and is formed by the coupling of one molecule of diiodotyrosine with one molecule of monoiodotyrosine. Thyroxine and triiodothyronine are stored in the thyroid colloid as thyroglobulin.

Thyroxine is the major component of normal secretions of the thyroid gland and is therefore the principal determinant of normal thyroid function. In normal human thyroid tissue, the thyroxine:triiodothyronine (T4:T3) ratio is 10:1 to 15:1. Therefore, adding thyroxine to the body will alter that ratio, causing an imbalance. The body's natural reaction will be to restore that balance, converting the excess T4 to T3.

I don't want to give numbers as to how much thyroxine to take, but start low, just like one would do with the T3 and then work up in increments until a beneficial result is seen. Patients with hypothyroidism (low thyroid hormone output) take up to 150 mcg of the drug to restore normal thyroid levels. Obviously as a bodybuilder trying to shed excess fat, we would want to exceed that level, increasing the metabolic rate. I do not know exactly how much would be necessary to create that effect.

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posted August 02, 2000 08:00 PM            

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Bump.

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posted August 02, 2000 10:39 PM            

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My mother has a prescription of Synthroid. Does anyone think it would be worth taking when I start my cutting cycle?

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