3-Cloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a rat thyroid gland carcinogen, does not affect serum levels of TSH and thyroid hormones

2000 ◽  
Vol 8 (4) ◽  
pp. 267-273 ◽  
Author(s):  
Hannu Komulainen ◽  
Raimo K Tuominen ◽  
Veli-Matti Kosma ◽  
Hannele Huuskonen
1978 ◽  
Vol 26 (12) ◽  
pp. 1121-1124 ◽  
Author(s):  
M Wilson ◽  
K R Hitchcock ◽  
R A DeLellis

Direct and indirect immunofluorescence techniques were used to localize the thyroid hormones triidothyronine (T3) and thyroxine (T4) in adult rat thyroid gland. Optimum dilutions of the antisera were established and four tissue fixatives were investigated for usefulness in this technique. Use of antibodies specific for either T3 or T4 resulted in brilliant fluorescence in the colloid pools and apical cytoplasm of follicular cells. In all cases, the adjacent parathyroid gland was devoid of fluorescence. This report demonstrates that these dipeptide hormones can be localized by using immunofluorescence techniques.


1961 ◽  
Vol 36 (2) ◽  
pp. 212-220 ◽  
Author(s):  
Shiro Iino

ABSTRACT The effect of various goitrogens on in vitro biosynthesis of thyroid horhomes was studied. The compounds in decreasing order of relative activity to completely inhibit DIT formation were 1-methyl-2-mercaptoimidazole (MIA), thiouracil (TU); propylthiouracil PTU) and goitrin; thiourea and methylthiouracil (MTU). Those in decreasing order of relative activity to completely inhibit MIT formation were MIA; PTU, MTU, TU and thiourea; goitrin. Of the compounds tested MIA was thus the most potent inhibitor of the rat thyroid gland in vitro. The conversion of monoiodotyrosine to diiodotyrosine was more sensitive to every goitrogen than the iodination of tyrosine to form monoiodotyrosine. The modes of action of these antithyroid drugs seemed to be approximately the same, except for goitrin, which showed very weak inhibition of MIT formation. Progoitrin, the precursor of goitrin, did not seem to possess any antithyroid activity.


1987 ◽  
Vol 35 (10) ◽  
pp. 1095-1104 ◽  
Author(s):  
P K Ring ◽  
V Johanson

We have developed a post-embedding immunogold technique for electron microscopic localization and quantitation of thyroglobulin (TG), thyroxine (T4), and triiodothyronine (T3) in rat thyroid. Labeling for TG was located on rough endoplasmic reticulum, Golgi apparatus, exocytotic vesicles, luminal colloid, colloid droplets, and lysosomes, whereas labeling for thyroid hormones was located on luminal colloid, colloid droplets, and lysosomes. We tested different procedures of fixation, dehydration, embedding, polymerization, and immunoincubation to optimize ultrastructural preservation and immunolabeling. Fixation with glutaraldehyde and osmium was possible with retained antigenicity. Dehydration temperature and the choice of embedding resin were the two crucial factors for good immunolabeling. Low-temperature dehydration greatly improved immunolabeling and could be combined with embedding in the methacrylate LR White or the epoxide Agar 100 (equivalent of Epon 812) polymerized at 40-60 degrees C, as the temperature during subsequent embedding and polymerization was of little importance for the immunoreactivity. Labeling on LR White sections was always higher than on Agar 100 sections. Various etching procedures were tested without improved specific labeling. Etching with hydrochloric acid gave nonspecific labeling of certain cell compartments.


1987 ◽  
Vol 25 (10) ◽  
pp. 787-794 ◽  
Author(s):  
C.G. Brown ◽  
R.F. Harland ◽  
I.R. Major ◽  
C.K. Atterwill

1982 ◽  
Vol 92 (3) ◽  
pp. 371-379 ◽  
Author(s):  
S.-Y. CHOW ◽  
J. W. KEMP ◽  
D. M. WOODBURY

The effects of thyrotrophin, hypophysectomy, and chronic treatment with thyroxine and methimazole on radioiodide uptake (thyroid/plasma (T/P) 125I− ratio), protein and DNA contents and activities of Na+,K+ -ATPase, HCO−3-ATPase, and carbonic anhydrase (CA) of rat thyroid gland were evaluated. Thyrotrophin given to intact rats slightly increased thyroid iodide uptake, did not affect protein or DNA content, and slightly inhibited CA activity (units/g cell water). Hypophysectomy markedly decreased T/P 125I− ratio, increased protein content, decreased activity of Na+,K+-ATPase, and slightly increased HCO−3-ATPase (nmol/mg DNA per min) and CA (units/g cell water) activities. Thyro-trophin given to hypophysectomized rats (as compared with untreated hypophysectomized control animals) markedly increased T/P 125I− ratio, slightly decreased protein content and decreased Na+,K+-ATPase and CA activities. Chronic treatment with methimazole increased T/P 125I− ratio, decreased protein content, markedly increased Na+,K+-ATPase and HCO−3-ATPase activities, and decreased CA activity. Chronic treatment with thyroxine, in contrast, decreased T/P 125I− ratio, decreased Na+,K+-ATPase activity, and increased CA activity. There was a significant inverse correlation between T/P 125I− ratio and CA activity in follicular cells for the various induced functional states of the thyroid.


Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1306-1313 ◽  
Author(s):  
Lutz Schomburg ◽  
Cornelia Riese ◽  
Marten Michaelis ◽  
Emine Griebert ◽  
Marc O. Klein ◽  
...  

The thyroid gland is rich in selenium (Se) and expresses a variety of selenoproteins that are involved in antioxidative defense and metabolism of thyroid hormones (TH). Se deficiency impairs regular synthesis of selenoproteins and adequate TH metabolism. We recently generated mice that lack the plasma Se carrier, selenoprotein P (SePP). SePP-knockout mice display decreased serum Se levels and manifest growth defects and neurological abnormalities partly reminiscent of thyroid gland dysfunction or profound hypothyroidism. Thus, we probed the TH axis in developing and adult SePP-knockout mice. Surprisingly, expression of Se-dependent 5′-deiodinase type 1 was only slightly altered in liver, kidney, or thyroid at postnatal d 60, and 5′-deiodinase type 2 activity in brain was normal in SePP-knockout mice. Thyroid gland morphology, thyroid glutathione peroxidase activity, thyroid Se concentration, and serum levels of TSH, T4, or T3 were within normal range. Pituitary TSHβ transcripts and hepatic 5′-deiodinase type 1 mRNA levels were unchanged, indicating regular T3 bioactivity in thyrotropes and hepatocytes. Cerebellar granule cell migration as a sensitive indicator of local T3 action during development was undisturbed. Collectively, these findings demonstrate that low levels of serum Se or SePP in the absence of other challenges do not necessarily interfere with regular functioning of the TH axis. 5′-deiodinase isozymes are preferentially supplied, and Se-dependent enzymes in the thyroid are even less-dependent on serum levels of Se or SePP than in brain. This indicates a top priority of the thyroid gland and its selenoenzymes with respect to the hierarchical Se supply within the organism.


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