Document Detail

Type 2 iodothyronine deiodinase is highly expressed in germ cells of adult rat testis.
MedLine Citation:
PMID:  17592020     Owner:  NLM     Status:  MEDLINE    
The testis has been classically described as a thyroid hormone unresponsive tissue, but recent studies indicate that these hormones might play an important role in developing testes. We have previously demonstrated that type 2 iodothyronine deiodinase (D2), a thyroid hormone-activating enzyme, is expressed in adult rodent testis and that its activity is induced by hypothyroidism. Nevertheless, the precise location of D2 in testis is not known. The aim of the present work was to determine the testicular cell types in which D2 is expressed using real-time PCR analysis, in situ hybridization histochemistry, and determination of D2 activity in cell fractions isolated from adult euthyroid and/or hypothyroid rat testis. The D2 mRNA levels in germ cells were higher than those from somatic cells (6.94 +/- 1.49 vs 2.32 +/- 0.79 arbitrary units (au); P = 0.017). Hypothyroidism increased D2 expression in germ cells (6.94 +/- 1.49 vs 8.78 +/- 5.43 au, P = 0.002) but did not change D2 transcripts in somatic cells significantly (2.12 +/- 0.79 vs 2.88 +/- 1.39 au, P = 0.50). In situ hybridization analysis showed that D2 mRNA is specifically present in elongated spermatids undergoing differentiation, whereas other germ cell types and Sertoli cells of seminiferous epithelium and the interstitial cells were virtually negative for this enzyme. The enzyme activity measured in germ and somatic isolated cell fractions (0.23 +/- 0.003 vs 0.02 +/- 0.013 fmol/min per mg protein respectively; P < 0.001) further confirmed the real-time PCR and in situ hybridization results. Hence, our findings demonstrated that D2 is predominantly expressed in elongated spermatids, suggesting that thyroid hormone might have a direct effect on spermatogenesis in the adult rats.
Simone Magagnin Wajner; Márcia dos Santos Wagner; Rossana C N Melo; Gleydes G Parreira; Hélio Chiarini-Garcia; Antonio C Bianco; Csaba Fekete; Edith Sanchez; Ronald M Lechan; Ana Luiza Maia
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of endocrinology     Volume:  194     ISSN:  0022-0795     ISO Abbreviation:  J. Endocrinol.     Publication Date:  2007 Jul 
Date Detail:
Created Date:  2007-06-26     Completed Date:  2007-09-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0375363     Medline TA:  J Endocrinol     Country:  England    
Other Details:
Languages:  eng     Pagination:  47-54     Citation Subset:  IM    
Endocrine Division, Thyroid Section, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
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MeSH Terms
Hypothyroidism / enzymology
In Situ Hybridization / methods
Iodide Peroxidase / genetics*
RNA, Messenger / analysis*
Rats, Wistar
Reverse Transcriptase Polymerase Chain Reaction / methods
Seminiferous Epithelium
Spermatids / cytology,  enzymology*
Spermatogenesis / physiology
Spermatozoa / cytology,  enzymology
Reg. No./Substance:
0/RNA, Messenger; EC 1.11.1.-/iodothyronine deiodinase type II; EC Peroxidase

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