Effects of nandrolone and resistance training on the blood pressure, cardiac electrophysiology, and expression of atrial beta-adrenergic receptors

Abstract

Aims: This study was performed to assess isolated and combined effects of nandrolone and resistance training on the blood pressure, cardiac electrophysiology, and expression of the beta(1)- and beta(2)-adrenergic receptors in the heart of rats.Main methods: Wistar rats were randomly divided into four groups and submitted to a 6-week treatment with nandrolone and/or resistance training. Cardiac hypertrophy was accessed by the ratio of heart weight to the final body weight. Blood pressure was determined by a computerized tail-cuff system. Electrocardiography analyses were performed. Western blotting was used to access the protein levels of the beta(1)- and beta(2)-adrenergic receptors in the right atrium and left ventricle.Key findings: Both resistance training and nandrolone induced cardiac hypertrophy. Nandrolone increased systolic blood pressure depending on the treatment time. Resistance training decreased systolic, diastolic and mean arterial blood pressure, as well as induced resting bradycardia. Nandrolone prolonged the QTc interval for both trained and non-trained groups when they were compared to their respective vehicle-treated one. Nandrolone increased the expression of beta(1)- and beta(2)-adrenergic receptors in the right atrium for both trained and non-trained groups when they were compared to their respective vehicle-treated one.Significance: This study indicated that nandrolone, associated or not with resistance training increases blood pressure depending on the treatment time, induces prolongation of the QTc interval, and increases the expression of beta(1)- and beta(2)-adrenergic receptors in the cardiac right atrium, but not in the left ventricle. (c) 2013 Published by Elsevier Inc.