Pikapolonica
Pridružen/-a: 24.06. 2006, 12:56
Prispevkov: 658
Kraj: Domžale
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 Objavljeno: 23 Maj 2007 14:40 Naslov sporočila: Zdravljenje s tiroksinom (ang + slo) |
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http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=185993
Replacement therapy for hypothyroidism with thyroxine alone does not ensure euthyroidism in all tissues, as studied in thyroidectomized rats.
H F Escobar-Morreale, M J Obregón, F Escobar del Rey, and G Morreale de Escobar
We have studied whether, or not, tissue-specific regulatory mechanisms provide normal 3,5,3'-triiodothyronine (T3) concentrations simultaneously in all tissues of a hypothyroid animal receiving thyroxine (T4), an assumption implicit in the replacement therapy of hypothyroid patients with T4 alone. Thyroidectomized rats were infused with placebo or 1 of 10 T4 doses (0.2-8.0 micrograms per 100 grams of body weight per day). Placebo-infused intact rats served as controls. Plasma and 10 tissues were obtained after 12-13 d of infusion. Plasma thyrotropin and plasma and tissue T4 and T3 were determined by RIA. Iodothyronine-deiodinase activities were assayed using cerebral cortex, liver, and lung. No single dose of T4 was able to restore normal plasma thyrotropin, T4 and T3, as well as T4 and T3 in all tissues, or at least to restore T3 simultaneously in plasma and all tissues. Moreover, in most tissues, the dose of T4 needed to ensure normal T3 levels resulted in supraphysiological T4 concentrations. Notable exceptions were the cortex, brown adipose tissue, and cerebellum, which maintained T3 homeostasis over a wide range of plasma T4 and T3 levels. Deiodinase activities explained some, but not all, of the tissue-specific and dose related changes in tissue T3 concentrations.
In conclusion, euthyroidism is not restored in plasma and all tissues of thyroidectomized rats on T4 alone. These results may well be pertinent to patients on T4 replacement therapy.
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Skratka pri podganah, ki so jih odstranili ščitnico so ugotovili, da samo z nadomeščanjem tiroksina (t4) ne morejo nikoli doseči ustreznih količin t3 in t4 v tkivih in v plazmi. To naj bi bilo pomembna informacija tudi pri zdravljenju ljudi.
V Sloveniji je trenutno na razpolago samo zdravilo s t4, saj naj bi zadoščalo...Kako pa je v praksi, pa dobro vemo ;-).
Mogoče pa bodo podgane pokazale, da imamo bolniki prav in da se evtirotični pacienti pogosto ne počutimo prav nič evtirotično  Dokler pa se podgane ne izkažejo, smo pa kar mi poskusne miške  .
Mogoče bi bilo res dobro registrirati kombinirane preparate. |
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