[Dynamics of diurnal content of carbohydrate metabolism intermediates in the rat liver].

Diurnal variations of glycolytic intermediates and Pi concentrations are studied in the laboratory rat liver. It is shown that tissue concentrations of glucose, glucose-6-phosphate and Pi vary synchronously during the day exhibiting maxima in light period and minima at night. Circadian fructose 1,6-diphosphate rhythm is similar to the rhythms of the metabolites mentioned above. Diurnal variations of the phosphoenolpyruvate and pyruvate content in the tissue are shifted up to 3-6 h. The data indicate that circadian regulation of hepatic carbohydrate energy metabolism did not take place at control points of gluconeogenesis only.