Acetylcarnitine formation during intense muscular contraction in humans.
To study the changes in carnitine during intense muscular effort subjects underwent 4 min intermittent electrical stimulation of the quadriceps femoris muscle and on a separate occasion performed 4 min exercise on a bicycle ergometer. Biopsies of the vastus lateralis muscle were taken at rest and after 2 and 4 min of stimulation or exercise. Resting mean muscle total carnitine content was 20.0 mmol/kg dry muscle. Approximately 77% was free carnitine and 19% acetylcarnitine. Four minutes of stimulation or intense exercise did not effect total carnitine but did result in a marked fall in free carnitine and almost equivalent rise in acetylcarnitine. The results indicate that acetylcarnitine is a major metabolite formed during intense muscular effort and that carnitine may function in the regulation of the acetyl-CoA/CoA ratio by buffering excess production of acetyl units.
D000108:Acetylcarnitine / Q000378:metabolism*; D000328:Adult; D002331:Carnitine / Q000031:analogs & derivatives* / Q000378:metabolism; D004558:Electric Stimulation; D006801:Humans; D007700:Kinetics; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism / Q000502:physiology*
D000108:Acetylcarnitine; D002331:Carnitine