Plasma N tau-methylhistidine concentration is a sensitive index of myofibrillar protein degradation during starvation in rats.

Urinary excretion of N tau-methylhistidine (MeHis) in rats was linearly elevated by starvation for 2 days. Plasma concentration of MeHis on day 1 and day 2 of starvation were increased 2.4- and 2.6-fold, respectively. The amount of released MeHis from the isolated muscles into medium during a 2-h incubation period was increased with starvation corresponded to the plasma MeHis concentration. The results of this study suggest that plasma MeHis is a sensitive index of myofibrillar protein degradation.