Effects of an androgenic steroid on exercise-induced cardiac remodeling in rats.
Habitual exercise results in a rightward shift in left ventricular end diastolic (LVED) pressure-volume or internal dimension (P-D) relationships [left ventricular (LV) remodeling]. However, exercise-mediated LV hypertrophy (LVH) produces an increased LV relative wall thickness [ratio (h/r) of wall thickness (h) to internal radius (r)] and hence a decrement in diastolic wall stress despite LV remodeling. In this study, the effect of chronic administration of an androgenic steroid on exercise-induced LV remodeling and h/r was examined in rats. Habitual exercise on voluntary running wheels resulted in LVH and a rightward shift in the LVED P-D relationships. However, LVH was sufficient to increase LVED h/r. Androgenic steroid administration to exercised rats, without influencing the development of exercise-induced LVH, produced a further rightward shift in the LVED P-D relationship associated with an increased diameter intercept. As a consequence, LVED h/r was reduced to control values. The steroid-mediated effects were not associated with alterations in either the quantity or quality of LV collagen. In conclusion, high-dose androgenic steroid administration alters exercise-induced LV remodeling and subsequently reduces the beneficial effect of physiological LVH on LV h/r.
Woodiwiss
A J
AJ
Laboratory of Cardiovascular Pathophysiology, Department of Physiology, University of the Witwatersrand, 2193 Johannesburg, South Africa.
Trifunovic
B
B
Philippides
M
M
Norton
G R
GR
D045930:Anabolic Agents / Q000494:pharmacology*; D000818:Animals; D003094:Collagen / Q000187:drug effects / Q000378:metabolism; D006321:Heart / Q000033:anatomy & histology; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013318:Stroke Volume / Q000187:drug effects / Q000502:physiology; D045165:Testosterone Congeners / Q000494:pharmacology*; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology; D020257:Ventricular Remodeling / Q000187:drug effects* / Q000502:physiology
D045930:Anabolic Agents; D045165:Testosterone Congeners; D003094:Collagen