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Mol Cell Endocrinol. 2018 Jan 15;460:14-23. doi: 10.1016/j.mce.2017.06.011. Epub 2017 Jun 9.

Testosterone deficiency prevents left ventricular contractility dysfunction after myocardial infarction.

Author information

1
Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil. Electronic address: rogeriofaustinoribeiro@hotmail.com.
2
Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil.
3
Department of Physiology and Biophysics, Universidade Federal de Minas Gerais, Minas Gerais, MG, Brazil.

Abstract

Testosterone may affect myocardial contractility since its deficiency decreases the contraction and relaxation of the heart. Meanwhile, testosterone replacement therapy has raised concerns because it may worsen cardiac dysfunction and remodeling after myocardial infarction (MI). In this study, we evaluate cardiac contractility 60 days after MI in rats with suppressed testosterone. Male Wistar rats underwent bilateral orchidectomy one week before the ligation of the anterior descending left coronary artery. The animals were divided into orchidectomized (OCT); MI; orchidectomized + MI (OCT + MI); orchidectomized + MI + testosterone (OCT + MI + T) and control (Sham) groups. Eight weeks after MI, papillary muscle contractility was analyzed under increasing calcium (0.62, 1.25, 2.5 and 3.75 mM) and isoproterenol (10-8 to 10-2 M) concentrations. Ventricular myocytes were isolated for intracellular calcium measurements and assessment of Ca2+ handling proteins. Contractility was preserved in the orchidectomized animals after myocardial infarction and was reduced when testosterone was replaced (Ca2+ 3.75 mM: Sham: 608 ± 70 (n = 11); OCT: 590 ± 37 (n = 16); MI: 311 ± 33* (n = 9); OCT + MI: 594 ± 76 (n = 7); OCT + MI + T: 433 ± 38* (n=4), g/g *p < 0.05 vs Sham). Orchidectomy also increased the Ca2+ transient amplitude of the ventricular myocytes and SERCA-2a protein expression levels. PLB phosphorylation levels at Thr17 were not different in the orchidectomized animals compared to the Sham animals but were reduced after testosterone replacement. CAMKII phosphorylation and protein nitrosylation increased in the orchidectomized animals. Our results support the view that testosterone deficiency prevents MI contractility dysfunction by altering the key proteins involved in Ca2+ handling.

KEYWORDS:

Cardiac contraction; Excitation-contraction coupling; Myocardial infarction; SERCA-2a; Testosterone

PMID:
28606867
DOI:
10.1016/j.mce.2017.06.011
[Indexed for MEDLINE]

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