title: Thyroid hormones alter the adenine nucleotide hydrolysis in adult rat blood serum.
abstract: The effects of ATP, ADP, and adenosine in the processes of platelet aggregation, vasodilatation, and coronary flow have been known for many years. The sequential hydrolysis of ATP to adenosine by soluble nucleotidases constitutes the main system for rapid inactivation of circulating adenine nucleotides. Thyroid disorders affect a number of biological factors including adenosine levels in different fractions. Then, we intend to investigate if the soluble nucleotidases responsible for the ATP, ADP, and AMP hydrolysis are affected by variations in the thyroid hormone levels in blood serum from adult rats. Hyperthyroidism was induced by daily intraperitoneal injections of L-thyroxine (T4) (2.5 and 10.0 μg/100 g body weight, respectively) for 7 or 14 days. Hypothyroidism was induced by thyroidectomy and methimazole (0.05%) added to their drinking water during 7 or 14 days. The treatments efficacy was confirmed by determination of hemodynamic parameters and cardiac hypertrophy evaluation. T4 treatment predominantly inhibited, and hypothyroidism (14 days after thyroidectomy) predominantly increased the ATP, ADP, and AMP hydrolysis in rat blood serum. These results suggest that both excess and deficiency of thyroid hormones can modulate the ATP diphosphohydrolase and 5'-nucleotidase activities in rat blood serum and consequently modulate the effects mediated by these enzymes and their products in vascular system.
authors.affiliation: Instituto Federal de Ensino, Ciência e Tecnologia do Rio Grande do Sul, Avenida Ipiranga 2752, Porto Alegre, RS, Brazil.
authors.forename: Alessandra Nejar
authors.initials: AN
authors.lastname: Bruno
authors.forename: Marcela Sorelli
authors.initials: MS
authors.lastname: Carneiro-Ramos
authors.forename: Andréia
authors.initials: A
authors.lastname: Buffon
authors.forename: Daniela
authors.initials: D
authors.lastname: Pochmann
authors.forename: Felipe Klein
authors.initials: FK
authors.lastname: Ricachenevsky
authors.forename: Maria Luiza M
authors.initials: ML
authors.lastname: Barreto-Chaves
authors.forename: João José Freitas
authors.initials: JJ
authors.lastname: Sarkis
mesh_terms: D000227:Adenine Nucleotides / Q000097:blood*; D000818:Animals; D013956:Antithyroid Agents; D057075:Enzyme Assays; D006439:Hemodynamics; D006868:Hydrolysis; D006980:Hyperthyroidism / Q000097:blood / Q000139:chemically induced; D007037:Hypothyroidism / Q000097:blood / Q000209:etiology; D008297:Male; D008713:Methimazole; D051381:Rats; D017208:Rats, Wistar; D013965:Thyroidectomy; D013974:Thyroxine / Q000172:deficiency / Q000502:physiology*
chemical_list: D000227:Adenine Nucleotides; D013956:Antithyroid Agents; D008713:Methimazole; D013974:Thyroxine