title: Thyroid hormone stimulates 5'-ecto-nucleotidase of neonatal rat ventricular myocytes.
abstract: Degradation of adenine nucleotides in myocardial cells has important physiological implications associated with the regulation of the high-energy phosphate precursor pool and the production of adenosine. Adenosine may be released as from cells or, following adenine nucleotides release, they may be metabolized and rapidly converted to adenosine via the action of an ectoenzyme cascade formed by an ATP diphosphohydrolase and a 5'-nucleotidase. Thyroid hormones are known to have profound effects on the cardiovascular system, as demonstrated by the changes accompanying both hypothyroidism and hyperthyroidism. We previously reported that thyroid hormone significantly increases the ecto-5'-nucleotidase (CD73) activity and expression in C6 glioma cells culture. The object of the present study was to evaluate the extracellular adenosine production from AMP in cardiomyocytes and also the effect of (T3) on activity and expression of the enzyme, CD73. Primary cultures of rat ventricular neonatal cardiac myocytes were submitted to increasing doses of T3 for 24 h. Cell viability and purity were estimated by measuring the release of lactate dehydrogenase (LDH) activity and immunofluorescence cell staining, respectively. CD73 activity was measurement using a malachite green method and RT-PCR was used to analyze enzyme expression. T3 stimulated CD73 activity and expression of the cells, suggesting that this effect could promote an increase in adenosine formation and, therefore, has an important modulatory role in the elicitation of responses that serve to restore the tissue oxygen supply-to-demand ratio back to normal.
authors.affiliation: Department of Histology and Embriology, Instituto de Ciências Biomédicas, University of São Paulo, SP Brazil.
authors.forename: Marcela Sorelli
authors.initials: MS
authors.lastname: Carneiro-Ramos
authors.forename: Vanessa Beatriz
authors.initials: VB
authors.lastname: da Silva
authors.forename: Marconi Barbosa
authors.initials: MB
authors.lastname: Coutinho
authors.forename: Ana Maria Oliveira
authors.initials: AM
authors.lastname: Battastini
authors.forename: João José Freitas
authors.initials: JJ
authors.lastname: Sarkis
authors.forename: Maria Luiza M
authors.initials: ML
authors.lastname: Barreto-Chaves
mesh_terms: D015720:5'-Nucleotidase / Q000096:biosynthesis; D000241:Adenosine / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D045744:Cell Line, Tumor; D002470:Cell Survival; D002478:Cells, Cultured; D006352:Heart Ventricles / Q000378:metabolism*; D006868:Hydrolysis; D007150:Immunohistochemistry; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008856:Microscopy, Fluorescence; D032383:Myocytes, Cardiac / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013963:Thyroid Hormones / Q000378:metabolism*; D013997:Time Factors
chemical_list: D010710:Phosphates; D013963:Thyroid Hormones; D000249:Adenosine Monophosphate; D012313:RNA; D007770:L-Lactate Dehydrogenase; D015720:5'-Nucleotidase; D000241:Adenosine; D010100:Oxygen