Data/hora: 04/06/2024 02:40:03

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Propranolol inhibits myocardial infarction-induced brown adipose tissue D2 activation and maintains a low thyroid hormone state in rats	
Autores: 	Seara,F.A.C.; Araujo,I.G.; Império,G.E.; Marassi,M.P.; Silva,A.C.M.; Mecawi,A.S.; Reis,L.C.; Olivares,E.L.	
Data: 	2019-01-01	
Ano: 	2019	
Palavras-chave: 	Myocardial infarction; Thyroid hormone; Deiodinase; Beta-blocker; Rats.	
Resumo: 	Considering the recognized role of thyroid hormones on the cardiovascular system during health and disease, we hypothesized that type 2 deiodinase (D2) activity, the main activation pathway of thyroxine (T4)-to-triiodothyronine (T3), could be an important site to modulate thyroid hormone status, which would then constitute a possible target for β-adrenergic blocking agents in a myocardial infarction (MI) model induced by left coronary occlusion in rats. Despite a sustained and dramatic fall in serum T4 concentrations (60–70%), the serum T3 concentration fell only transiently in the first week post-infarction (53%) and returned to control levels at 8 and 12 weeks after surgery compared to the Sham group (P&lt;0.05). Brown adipose tissue (BAT) D2 activity (fmol T4·min-1·mg ptn-1) was significantly increased by approximately 77% in the 8th week and approximately 100% in the 12th week in the MI group compared to that of the Sham group (P&lt;0.05). Beta-blocker treatment (0.5 g/L propranolol given in the drinking water) maintained a low T3 state in MI animals, dampening both BAT D2 activity (44% reduction) and serum T3 (66% reduction in serum T3) compared to that of the non-treated MI group 12 weeks after surgery (P&lt;0.05). Propranolol improved cardiac function (assessed by echocardiogram) in the MI group compared to the non-treated MI group by 40 and 57%, 1 and 12 weeks after treatment, respectively (P&lt;0.05). Our data suggested that the beta-adrenergic pathway may contribute to BAT D2 hyperactivity and T3 normalization after MI in rats. Propranolol treatment maintained low T3 state and improved cardiac function additionally.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2019001000609	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/1414-431x20198491	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.52 n.10 2019	
Fonte: 	info:eu-repo/semantics/openAccess