Circadian Rhythm for Tryptophan Pyrrolase Activit and Its Circulating Substrate

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Science  30 Sep 1966:
Vol. 153, Issue 3744, pp. 1642-1644
DOI: 10.1126/science.153.3744.1642


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.