Lactate dehydrogenase regulation in aged skeletal muscle: Regulation by anabolic steroids and functional overload

Abstract Aging alters the skeletal muscle response to overload-induced growth. The onset of functional overload is characterized by increased myoblast proliferation and an altered muscle metabolic profile. The onset of functional overload is associated with increased energy demands that are met through the interconversion of lactate and pyruvate via the activity of lactate dehydrogenase (LDH). Testosterone targets many of the processes activated at the onset of functional overload. However, the effect of aging on this metabolic plasticity at the onset of functional overload and how anabolic steroid administration modulates this response is not well understood. The purpose of this study was to determine if aging would alter overload-induced LDH activity and expression at the onset of functional overload and whether anabolic steroid administration would modulate this response. Five-month and 25-month male Fischer 344 x F 1 BRN were given nandrolone decanoate (ND) or sham injections for 14 days and then the plantaris was functionally overloaded (OV) for 3 days by synergist ablation. Aging reduced muscle LDH-A & LDH-B activity 70% (p