[Use of fructose as an energy substrate in the body of rats given food containing various amounts of carbohydrate].

Production of radioactive CO2 from 14C-fructose administered intraperitoneally was studied in 18 male Wistar rats given food containing saccharose with calorific value of 0-56%. Intensive CO2 labeling was completed 3-4 h after 14C-fructose administration. More radioactive CO2 was formed in rats which received food without fructose, during first 30-60 min after 14C-fructose administration. About 20-30% of radioactivity introduced with fructose was excreted from the body with CO2 expired during 6 h, that correlated with the data on CO2 production from glucose. Thus, despite a number of principle differences in fructose and glucose metabolism, similar portions of their pool are used for direct provision of the body with energy.