Cardiovascular Pharmacology: Open Access

Abstract

Supraphysiological Testosterone Levels Shorten the QT Interval but do Not Alter Total Anatomic Myocardial Infarct Size in Rabbits with Acute Myocardial Infarction

Michael J. Herring, Sharon L. Hale, Jianru Shi, Peyman Mesbah Oskui, Gregory Kay and Robert A. Kloner

Introduction: A growing number of men are using exogenous testosterone (T) to treat hypogonadism and to enhance athletic performance. However, some studies suggested that T increased adverse cardiovascular events. Although T has been shown to increase apoptosis, its effect on total acute myocardial infarction (MI) size is largely unknown. We hypothesized that T might increase MI size.

Materials and Methods: Male rabbits received an intramuscular injection of either T (50 mg/kg) or saline one week before receiving 30 minutes of coronary artery occlusion/3 hours of coronary artery reperfusion.

Results: The T levels in the treated group were higher than those of the control group: 15 ± 1 ng/mL T (n=18) versus 1 ± 1 ng/mL control (n= 20, P<0.01). Anatomic MI size (tetrazolium staining) expressed as a percentage of the ischemic risk zone (blue dye technique) was similar in both groups: 37 ± 3% in controls and 37 ± 5% in the T group (P= 0.96). T significantly shortened the QTc interval by 9% (P=0.03).

Conclusions: Supra physiological levels of T did not increase infarct size. T shortened the QTc interval, which may create an anti-arrhythmic substrate.