| Sarcopenia is the loss of muscle mass and strength that occurs with aging. Here we examine the effects of aging and gender on the regulation of molecules believed to regulate muscle growth and adaptation in the F344/BN rat. In male animals, soleus and EDL muscle/body weight ratio declined continuously with aging while muscle atrophy in female animals plateaued at 26-months and remained constant thereafter. Aging increased the phosphorylation of protein kinase-B (Akt) and the mammalian target of rapamycin (mTOR) in the female but not male soleus muscle. This finding was associated with the attenuation of muscle atrophy observed in female animals. Male and female soleus muscles exhibited higher p70S6k phosphorylation with aging. Irrespective of muscle type or gender, aging was associated with increased calcineurin expression. Taken together, these data suggest that indices of protein synthesis and muscle adaptation are regulated differently with aging in different muscle types and gender.;(Keywords: Aging, sarcopenia, F344/BN, muscle, gender, soleus, EDL, diaphragm)... |
