Abstract
During the course of a study on the deleterious effects of sucrose, we previously demonstrated that prolonged excess sucrose administration increased the liquid intake and urine volume of rats, and produced a diabetes-like pathema. It was also shown that urinary Ca and P excretion, and the levels of blood glucose, pyruvic and lactic acids were increased, indicative of metabolic acidosis. In order to clarify the above observations, the present study was undertaken to investigate the digestion and absorption of sucrose and also sucrase activity in the small intestinal mucosa of rats following prolonged administration of excess sucrose. Wistar-strain male rats were divided into 2 groups (5 rats/group): Group 1 (G1) and Group 2 (G2) were given purified water and 10% sucrose ad libitum for 5 months, respectively. The rats were then fasted for 24h and anesthetized with pentobarbital. Perfusion cannulae were inserted from the upper duodenum and lower ileum. Sodium phosphate buffer (37°C) containing sucrose was perfused at a rate of 1ml/min via the upper cannula for 60min. Fractions (4ml) were then collected via the lower cannula and subjected to glucose and sucrose assays. Sucrase activity in the small intestinal mucosa was also determined. The rates of digestion and absorption of sucrose in G2 were significantly increased, together with a remarkable increase of sucrase activity. Significant relationships between sucrose digestion-absorption and sucrase activity were obtained in both G1 and G2. These results indicate that prolonged excess sucrose intake in rats results in increased sucrose digestion and a higher absorption rate due to enhanced sucrase activity.
