Effect of histidine-free and -excess diets on anserine and carnosine contents in rat gastrocnemius muscle.

Anserine and carnosine contents were determined in muscle of rats subjected to histidine depletion or excessive supplement. The contents of anserine and carnosine were reduced in the gastrocnemius muscle of rats fed a histidine-free diet. The diet showed especially a remarkable decrease of carnosine content. After rehabilitation for one week, the muscle anserine and carnosine contents in histidine-deficient rat returned to the normal level. The body and gastrocnemius muscle weight were decreased in rats fed a histidine-excess diet. However, anserine and carnosine content in muscle of rats fed a histidine-excess diet were twice of that of control rats. Urinary excretion of Npi-methylhistidine and Npi-methylhistidine was increased in rats fed a histidine-excess diet.