ABSTRACT
The anabolic androgenic steroids are known to stimulate muscle protein synthesis and hypertrophy. Cardiomyocytes have two types of ATP-sensitive potassium channels in sarcolemma [sarck[ATP]] and in mitochondria [mitk[ATP]]. Activation of the sarck[ATP] channels has been proposed to protect against ischemia-reperfusion injury. This study aimed to investigate the effect of nandrolone decanoate [ND] on the expression of sarck[ATP] channels in the presence and absence of exercise in rat heart. In this experimental study, 40 adult male rats were divided into five groups: control, vehicle, ND, exercise and exercise-ND group. Rats in the exercise group were submitted to a running program on a treadmill, 5 days a week for 10 weeks. In addition, rats in the ND and exercise-ND groups received a weekly intramuscular injection of ND [10 mg/kg] for 10 weeks. Expression of the K[ATP] channel subunits [Kir6.2 and SUR2] was determined using the Western blotting method. ND administration had no effect on the expression of sarck[ATP] channel subunits in the sedentary group, while the chronic exercise significantly increased the expression of K[ATP] channel subunits [P=0.01]. Moreover, the ND administration significantly decreased the Kir6.2 [P=0.001] and SUR2 [P=0.05] subunits in the exercised animals. Chronic exercise and ND increases the expression of sarc[KATP] channels, and. The ND-induced expression decrement of channels is probably one of the mechanisms involved in the impairment of exercise-induced cardioprotection in rat heart