Exercise training decreases the concentration of malonyl-CoA and increases the expression and activity of malonyl-CoA decarboxylase in human muscle

The study was designed to evaluate whether changes in malonyl-CoA and the enzymes that govern its concentration occur in human muscle as a result of physical training. Healthy, middle-aged subjects were studied before and after a 12-wk training program that significantly increased Vo2 max by 13% and decreased intra-abdominal fat by 17%. Significant decreases (25–30%) in the concentration of malonyl-CoA were observed after training, 24–36 h after the last bout of exercise. They were accompanied by increases in both the activity (88%) and mRNA (51%) of malonyl-CoA decarboxylase (MCD) in muscle but no changes in the phosphorylation of AMP kinase (AMPK, Thr172) or of acetyl-CoA carboxylase. The abundance of peroxisome proliferator-activated receptor (PPAR)γ coactivator-1α (PGC-1α), a regulator of transcription that has been linked to the mediation of MCD expression by PPARα, was also increased (3-fold). In studies also conducted 24–36 h after the last bout of exercise, no evidence of increased whole body ins...