[Circadian rhythm of intestinal glucose absorption in fasting and fed rats].

Under conditions of chronic experiment the circadian cycle of glucose transport was determined. An isolated proximal area of the small intestine was perfused by glucose, fructose, medical bile and Ringer's solutions in various intervals of the 24 hour period. The circadian cycle of glucose absorption is disturbed in the fasting rats. Various substrates differently alter their amplitude and acro-phase of absorption. Ringer's solution perfusion shifts the acro-phase absorption to evening time, while that of fructose occurs during day time and that of bile takes place at night. The circadian cycle of the fed rats is less subject to shifts. Fasting is a powerful exogenous factor causing structural changes in the small intestine and altering the circadian cycle of glucose absorption.