Temporal expression of thyroid hormone receptor alpha1 in the liver of the lizard Podarcis sicula

The effects of thyroid hormones on metabolism and development are mediated by thyroid hormone receptors (TRs). To gain a better understanding of the potential role of thyroid hormone receptors in the liver of the lizard Podarcis sicula, we have evaluated the expression of TRs during the more critica...

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Bibliographic Details
Published in:Journal of experimental zoology. Part A, Comparative experimental biology Comparative experimental biology, 2004-03, Vol.301 (3), p.212-217
Main Authors: Virgilio, Francesca, Sciarrillo, Rosaria, De Falco, Maria, Comitato, Raffaella, Laforgia, Vincenza, Varano, Lorenzo, Cardone, Anna
Format: Article
Language:English
Subjects:
Analysis of Variance
Animals
Autoradiography
Blotting, Northern
Gene Expression
Immunohistochemistry
Italy
Liver - metabolism
Lizards - metabolism
Periodicity
RNA Precursors - genetics
RNA Precursors - metabolism
RNA, Messenger - genetics
RNA, Messenger - metabolism
Thyroid Hormone Receptors alpha - genetics
Thyroid Hormone Receptors alpha - metabolism
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Summary:The effects of thyroid hormones on metabolism and development are mediated by thyroid hormone receptors (TRs). To gain a better understanding of the potential role of thyroid hormone receptors in the liver of the lizard Podarcis sicula, we have evaluated the expression of TRs during the more critical periods of the annual variations of thyroid activity. The results obtained have indicated that in the liver of the lizard P. sicula there are three transcripts: mRNA of 5.0 kb for TRalpha1, mRNA of 2.6 kb for TRalpha2, and 6.0 kb band, which represent unprocessed heteronuclear RNA, encoding unspliced primary transcripts of RNA prior to their processing into the mature TRalpha1 and TRalpha2. By means of slot-blot, we are able to determine that there is a change in the expression of TRs that occurs in the liver during the annual cycle of thyroid activity. A major expression registers in May, when the lizard thyroid gland shows the maximal activity. The combination of molecular biology with immunohistochemistry revealed that hepatic cells were also TRalpha IR positive. Particularly intense immunostaining was present in the cell nuclei of animals sacrified in May. These observations suggest that in lizard P. sicula the thyroid hormone (T3) might regulate hepatic activity, modulating TR mRNA levels.
ISSN:1548-8969