Carnosine loading and washout in human skeletal muscles.

Carnosine (beta-alanyl-L-histidine) is present in high concentrations in human skeletal muscles. The oral ingestion of beta-alanine, the rate-limiting precursor in carnosine synthesis, has been shown to elevate the muscle carnosine content both in trained and untrained humans. Little human data exist about the dynamics of the muscle carnosine content, its metabolic regulation, and its dependence on muscle fiber type.