Circadian Rhythm for Tryptophan Pyrrolase Activity and Its Circulating Substrate

Abstract

Hepatic tryptophan pyrrolase and its circulating substrate, whole blood tryptophan, have a circadian rhythmicity in mice. Intact adrenocortical function is required for the normal rhythmicity of both enzyme and substrate although an altered but less apparent rhythm persists in the adrenalectomized state.