section_path: Endocrine functions of skeletal muscle/Skeletal muscle secretome alters with exercise
section_name: Skeletal muscle secretome alters with exercise
paragraph_text: Skeletal muscle secretome alters with exercise
  
  Williams et al. obtained biopsies of a thigh skeletal muscle (vastus lateralis muscle) of eight 23-year old, originally sedentary, Caucasian males. Biopsies were taken both before and after a six-week long endurance exercise training program. The exercise consisted of riding a stationary bicycle for one hour, five days a week for six weeks.
  
  Of the 13,108 genes with detected expression in the muscle biopsies, 641 genes were upregulated after endurance training and 176 genes were downregulated. Of the 817 total altered genes, 531 were identified as being in the secretome by either or both of Uniprot or Exocarta, or else by studies investigating the secretome of muscle cells. Because many of the exercise-regulated genes are identified as secreted, this indicates that much of the effect of exercise has an endocrine rather than metabolic function. The main pathways found to be affected by secreted exercise-regulated proteins were related to cardiac, cognitive, kidney and platelet functions.