Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Sensitivity of thyroid gland growth to thyroid stimulating hormone (TSH) in rats treated with antithyroid drugs
Autore:
Hood, A; Liu, YP; Gattone, VH; Klaassen, CD;
Indirizzi:
Univ Kansas, Med Ctr, Dept Pharmacol Toxicol & Therapeut, Kansas City, KS 66103 USA Univ Kansas Kansas City KS USA 66103 Therapeut, Kansas City, KS 66103 USA Univ Kansas, Med Ctr, Dept Anat & Cell Biol, Kansas City, KS 66103 USA Univ Kansas Kansas City KS USA 66103 Cell Biol, Kansas City, KS 66103 USA
Titolo Testata:
TOXICOLOGICAL SCIENCES
fascicolo: 2, volume: 49, anno: 1999,
pagine: 263 - 271
SICI:
1096-6080(199906)49:2<263:SOTGGT>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
UDP-GLUCURONOSYLTRANSFERASE INDUCERS; PROPYLTHIOURACIL PTU; MECHANISM; METABOLISM; N-BIS(2-HYDROXYPROPYL)NITROSAMINE; TUMORS;
Keywords:
thyroid stimulating hormone (TSH); thyroxine (T-4); triiodothyronine (T-3); propylthiouracil (PTU); methimazole (MMI); phenobarbitol (PB); thyroid follicular cell proliferation; rat;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Klaassen, CD Univ Kansas, Med Ctr, Dept Pharmacol Toxicol & Therapeut, Kansas City, KS 66103 USA Univ Kansas Kansas City KS USA 66103 nsas City, KS 66103 USA
Citazione:
A. Hood et al., "Sensitivity of thyroid gland growth to thyroid stimulating hormone (TSH) in rats treated with antithyroid drugs", TOXICOL SCI, 49(2), 1999, pp. 263-271

Abstract

Antithyroid drugs and phenobarbital (PB) have been shown to promote thyroid tumors in rats. It has been proposed that increased thyroid-stimulating hormone (TSH) mediates the thyroid tumor-promoting effect of antithyroid drugs and PB, and is increased because of decreased thyroxine (T-4) concentration. However, PB is much less effective than antithyroid drugs at increasing TSH. It has been proposed that small increases in serum TSH produced by PB treatment is sufficient to promote thyroid tumors. However, the level to which TSH must be increased to stimulate the thyroid gland has not been reported. Therefore, we have examined the effect of increasing serum TSH concentration on thyroid growth by measuring thyroid gland weight and thyroid follicular cell proliferation. Serum TSH concentrations were increased by feeding rats various concentrations of propylthiouracil (PTU) or methimazole (MMI) for 21 days. Serum total T-4, free T-4, total T-3 (triiodothyronine), free T-3, and TSH concentrations were measured by radioimmunoassay. Thyroidfollicular cell proliferation was measured by autoradiography and expressed as a labeling index (LI). PTU and MMI treatments reduced total and free T-4 more than 95% by day 21, whereas total and free T-3 were reduced 60%. TSH, thyroid follicular cell proliferation and thyroid weight were increased 560%, 1400%, and 200%, respectively, by day 21. TSH was significantly correlated with thyroid weight and LI. Moderate increases in serum TSH of between 10 and 20 ng/ml increased the number of proliferating thyroid follicular cells, but had no effect on thyroid weight. These results support that small increases in serum TSH can be sufficient to stimulate thyroid follicular cell proliferation. Furthermore, thyroid follicular cell proliferation may be more useful than thyroid weight alone for assessing alterations in thyroid growth in rats treated with chemicals that produce only small to moderate increases in serum TSH.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 03:29:29