CHAPTER 15: Human Skeletal Muscle Carnosine and Its Function: A Focus on Homeostasis, Muscle Contractility and pH

Carnosine, but not anserine, is present in relatively high concentrations in human skeletal muscle. Young, male subjects with a high proportion of fast-twitch muscle fibers have the highest carnosine concentration within in a healthy population. Human muscle carnosine stores can be markedly enhanced by long-term supplementation of β-alanine (3–6 g for at least 4 weeks), the rate-limiting amino acid for carnosine synthesis. Elevated muscle carnosine levels have been shown to be ergogenic for some high-intensity exercises that last at least 1 min. Although more in vivo human research is needed concerning the underlying ergogenic mechanism, in vitro data suggest that both an enhanced intramyocellular pH buffering and calcium handling could explain (partly) the ergogenic effect of elevated carnosine stores. This chapter further discusses the possible release of carnosine from skeletal muscle into the circulation and its function to act as a depot for the histidine–histamine pathway.