Effect of fasting on the intestinal absorption of D-glucose and D-xylose in rats in vivo.

The present study was planned to elucidate the role of fasting on the intestinal absorption of monosaccharides particularly--glucose and xylose in inbred female albino rats. Rats (weighing 250-300 grams) were divided into three groups. One group of rats served as control while the other two were experimental. One of the experimental groups was starved for 48 hours while the other for a period of 72 hours. It was found that fasting for 72 hours causes an overall increase in absorption of glucose from small intestine. Forty-eight hours of fasting caused a significant increase in glucose absorption from distal ileum only. Increase in the glucose absorption in fasting from small intestine can well be explained on the basis of a reduction in glucose metabolism in general as an adaptation to starvation so as to leave more glucose for cerebral metabolism. No significant changes, whatsoever, were encountered with xylose absorption in fasting animals.