EFFECTS OF ANABOLIC-STEROIDS AND ENDURANCE EXERCISE ON CARDIAC-PERFORMANCE

This study examined the effects of anabolic steroids and exhaustive en durance exercise, and the combination of both treatments on in vitro c ardiac contractile function. Fifty-two male Sprague-Dawley rats were r andomly assigned, in groups of 13, to one of the four groups: sedentar y control (C), steroid-treated (ST), exercise-trained (E), and exercis e plus steroid treated (E + S). Nandrolone decanoate was administered to the steroid-treated groups every 7-9 days during the 10 weeks study , while the C and E groups received glycerol injection on these occasi ons. The exercised rats ran on a treadmill wearing a collar weight (2 - 3 % of body weight) for 50 min, 5 days a week. In vitro ventricular performance was assessed in isolated Langendorff perfused hearts in re sponse to increasing left ventricular balloon volumes. Left ventricula r + dP/dt, dP/dt at 60 mmHg developed pressure, tension time index, an d Emax (slope of the pressure-volume curves) were significantly (p < 0 .05) lowered in the E + S group, as compared to the C, E, or ST group. Meanwhile, the E group exhibited a higher (p < 0.05) 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 rat io were detected among the four groups. Rats subjected to endurance ex ercise or anabolic steroid treatment alone exhibited no change in LV f unction. It is concluded that 1) anabolic steroid treatment in combina tion with endurance exercise produced a depressive effect on cardiac c ontractile function when compared to endurance exercise training or st eroid treatment alone, and 2) cardiac contractile function was not alt ered following endurance exercise training or anabolic steroid treatme nt alone.