The Effect Of Exercise On The Level Of Androgen And Its Receptor During Disuse Atrophy Of Skeletal Muscle And Rehabilitation In Rats

The capacity of androgen receptor (AR) binding in quadriceps femoris muscle and the level of serum testosterone (ST) were investigated during disuse atrophy of skeletal muscle and natural,exercise rehabilitation in male rats. After three weeks of immobilization of lower limbs in rats,the ST level and AR binding capacity were 0.58 +0.24 nmol/L,7.99 + 2.19 fmol/mg respectively and significantly decreased compared with control (6.21+3.51 nmol/L,11.61 +2.96 fmol/mg). And the AR binding capacity (10.41 +3.90 fmol/mg) of the natural rehabilitation group returned to control,but the ST level (1.93 +0.77 nmol/L) was lower than control. Both moderate intensity of treadmill and swimming training increased the AR binding capacity (25.70+7.53 fmol/mg,14.79+0.76 fmol/mg respectively) to be higher than control and the natural rehabilitation group. Meanwhile,the ST level (3.71 +2.84 nmol/L) of the swimming group returned to control. But the difference of ST between the exercise groups and the natural rehabilitation group was not distinct. According to the results,we conclude that:immobilization could result in disuse atrophy of skeletal muscle. After free mobilization,skeletal muscle can be rehabilitated gradually. A suitable exercise could accelerate the course of rehabilitation,which may be relative to enhancing the ST level and AR binding capacity of local muscle tissues and promoting the synthesis of muscle protein. Furthermore,the effect of exercise on the AR binding capacity is larger than that on the ST level. The AR binding capacity may have much more significance than the ST level to the assimilation of skeletal muscle. In addition,treadmill and swimming training are more effective to the increase of the AR binding capacity and the ST level respectively,so we should consider all kinds of factors such as exercise intensity and time to acquire the best training protocol.