Cosinor analysis of circadian oscillations of amino acid catabolizing enzymes in temporal pattern of nutrient input.

Circadian oscillations of liver tyrosine aminotransferase (TAT) tryptophan oxygenase (TO), alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), and glutamate dehydrogenase (GLDH) in temporal pattern of protein input have been investigated. Cosinor analysis of oscillations parameters revealed the glucocorticoid induction of TO activity and protein induction of TAT activity rhythm. ALAT, ASAT, and GLDH activities showed 24 h fluctuations, but the regulation mechanisms remain unclear.