Abstract

This study examined the effects of anabolic steroids and exhaustive endurance exercise, and the combination of both on in vitro cardiac contractile function. 52 male Sprague-Dawley rats were randomly assigned to one of 4 groups: sedentary control (C), steroid-treated (ST), exercise-trained (E), and exercise plus steroid treated (E+S). Nandrolone decanoate was administered to the ST groups every 7-9 d during the 10 wk study. The E rats ran on a treadmill wearing a collar weight (2-3 BW) for 50 min, 5 d/wk. In vitro ventricular performance was assessed in isolated Langendorff perfused hearts in response to increasing left ventricular balloon volumes. Left ventricular +dP/dt, dP/dt at 60 mmHg developed pressure, tension time index, and Emax (slope of pressure-volume curves) were significantly lowered in the E+S group, as compared to the C, E, or ST group. Meanwhile, the E group exhibited a higher left ventricular systolic pressure (LVSP) than the C and E+S groups. No significant differences in dP/dt/P, heart weight (wt), and heart wt to body wt ratio were detected among the 4 groups. Rats subjected to endurance exercise or anabolic steroid treatment alone exhibited no change in LV function. It is concluded that 1) anabolic steroid treatment in combination with endurance exercise produced a depressive effect on cardiac contractile function when compared to endurance training or steroid treatment alone, and 2) cardiac contractile function was not altered after endurance training or anabolic steroid treatment alone. Verf.-Referat