Animal thyroid

Thyroid hormones used in medicine include both the natural and synthetic hormones. The synthetic hormones are generally preferred because they are more uniform in potency than are the natural hormones obtained from animals. Thyroid hormones are listed in the Summary Drug Table Thyroid and Antithyroid Dragp. 

Oral intake of 0.89 Bq 129l, whole animal Thyroid contained 0.97 Bq 129l/kg fresh weight (FW) vs. <0.0012 Bq/kg FW for all other tissues 2... 

Research Laboratories 1984). Effects observed in both sexes included significantly reduced plasma T4 levels at 10 mg/kg/day and increased follicular cell hyperplasia at 100 mg/kg/day. Incidences of follicular cell hyperplasia in the 0, 2, 10, and 100 mg/kg/day dose groups of this study were 0/10, 2/10, 2/10, and 5/10 in males and 0/10, 0/10, 1/10, and 4/10 in females. The thyroid hyperplasia was mild and transient as it was characterized as very slight in severity at all doses and was no longer observed at 24 weeks postexposure in any animals. Thyroid hyperplasia was equivocally increased in male CD rats that were exposed to 90 mg/kg/day of pentaBDE (unspecified mixture) in the diet for 28 days (IRDC... 

Parker, S.J. and Specker, J.L. (1990). Salinity and temperature effects on whole-animal thyroid hormone levels in larval and juvenile striped bass, Morone saxatilis. Fish Physiology and Biochemistry 8,507-514. 

Failure of the thyroid to produce sufficient thyroid hormone is the most common cause of hypothyroidism and is known as primary hypothyroidism. Secondary hypothyroidism occurs much less often and results from diminished release of TSH from the pituitary. Treatment of hypothyroidism is achieved by the replacement of thyroid hormone, primarily T4. A synthetic preparation of T4 is available, levothyroxine (Synthroid ), which has been a popular choice for hypothyroidism because of its consistent potency and prolonged duration of action. No toxicity occurs when given in physiological replacement doses. Desiccated animal thyroid is also available at a lesser cost. Overdoses cause symptoms of hyperthyroidism and can be used as a guide in clinical management. Hypothyroidism is not cured by the daily intake of thyroid hormone it is a life-long regimen. 

Substantial l29I concentrations have been detected in animal thyroids collected in the neighbourhood of a nuclear fuel reprocessing plant in West Valley, N.Y.2... 

Van Middlesworth L and Handl J (1997) I in animal thyroids after the Chernobyl nuclear accident. Health Phys. 73(4) 647—650. 

The synthetic preparations used are the sodium salts of the natural isomers of the thyroid hormones. Levothyroxine sodium (L-T, synthroid, levoxyl, levothroid, unithroid, others) is available in tablets in a variety of doses and as a lyophilized powder for injection. L-T has a narrow therapeutic index, and the FDA has mandated demonstration of bioequivalence for brand and generic preparations by the various producers. Liothyronine sodium (L-Tft is available in tablets (cytomel) and in an injectable form (triostat). A mixture of L-T and L-T is marketed as liotrix (thyroiar). Desiccated thyroid preparations, derived from whole animal thyroids and containing both T and T have highly variable biologic activity and are much less desirable. 

Thyroid honnones used in medicine include botii tiie natural and syntiietic honnones. The syntiietic hormones are generally preferred because tiiey are more mii-fonn in potency tiian are tiie natural honnones obtained from animals. Thyroid honnones are listed in tiie Suinmaiy Dmg Table Thyroid and Antitiiyroid Dm. ... 

High I29j/I27j Jgvels in animal thyroid has been observed in the vicinity of nuclear facilities, especially reprocessing plants. I29j/i27j g,f (1-250) X 10 in bovine thy-... 

Table 46.5 Comparison of level in human and animal thyroids from different places ...

Thyroid hormone preparations belong to two categories natural hormone preparations derived from animal thyroid, and synthetic preparations. 

Exposure Routes, Symptoms, Target Organs (see Table 5) ER Inh. Abs. Ing. Con SY Irrit eyes. skin, resp sys CNS depres [care] TO Eyes. skin, resp sys. CNS [in animals thyroid gland tumors] First Aid (see Tabie 6) Eye Irr immed Skin Water flush immed Breath Resp support Swallow Medical attention immed ... 

Thyroid hormone is available as synthetic triiodothyronine (T3, or liothyronine), synthetic tetraiodothyronine (T4, levothyroxine), or natural desiccated animal thyroid (containing both T3 and T4 Table 11-55). Despite concern over the potentially life-threatening manifestations of thyrotoxicosis, serious toxicity rarely occurs after acute thyroid hormone ingestion. 

Air Vegetables Direct radiation Air Milk Vegetables Air Animal thyroids Forage Air Vegetables Milk Direct radiation Deposition Forage Air Deposition Terrestrial biota Soil... 

Wogman, N.A., Brodzinski, R.L., and Van Middlesworth, L. (1977). Radium accumulation in animal thyroid glands a possible method for uranium and thorium prospecting, J. Radioanal. Chem. 41, 115-125. 

From about 1945, the atom ratio of I to stable I in the environment has been increasing because of the I added to the environment by nuclear weapons testing and nuclear facilities. Based on a small number of samples of animal thyroids from locations remote from nuclear facilities, the ratio of was 10 to 10" in the 1960 s... 

Smith, D.D. (1977). in Animal Thyroids from Nevada and Other Western States, Report No. EPA-600/3-77-067 (U.S. Environmental Protection Agency, Las Vegas, Nevada). 

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