Abstract
The experiment of 59Fe utilization was carried out by oral administration of 59Fe material given to two groups of rats, which were fed on low protein-adepuate iron diets for 52 days (Exp. 1) and low protein-low iron diets for 35 days (Exp. 2), and by detecting the rate of 59Fe incorporation into red blood cells and liver-nonhemin-iron after 48 hours of giving the dose.
During feeding on them, averages of the weight gain of the rats fed on the diets of 5, 10, 15 and 20% casein in Exp. 1 (Fe content: 35. 2mg%) were 0.1, 1.0, 1.8 and 4.0 g/day, and those fed on the diets of 5 and 20% casein in Exp. 2 (Fe content: 0.08 and 0.31mg%) were 0.4 and 3.9g/day respectively.
At the end of the feeding, almost no decrease of hemoglobin concentration was observed in all experimental groups with a exception of 8.7g/dl hemoglobin in the rats fed on 20% casein in Exp. 2. And nonhemin iron content in liver was on a normal level in Exp. 1 (102.2-184.4μg/g), but that of rats fed on 5% and 20% casein diets in Exp. 2 was 71.9 and 34.8μg/g respectively.
59Fe incorporation into red blood cells in rats of Exp. 1 was 9.8, 21.3, 23.0 and 45.5%, and that in Exp. 2 was 12.7 and 43.6% of total 59Fe given to rats in the same order mentioned above. 59Fe incorporation into liver-nonhemin-iron was 4.0, 7.5, 7.8 and 8.2% in rats of Exp. 1, and that in Exp. 2 was 4.5 and 1.5% respectively. Accordingly 59Fe incorporation into red blood cells in the rats of 5% casein diet was significantly less than that in the rats of 20% casein in both series of experiments (p<0.001 in both cases).
Xanthine oxidase activity in liver was parallel to the amounts of protein (casein) ingested, and increase of the activity was observed extraordinarily in the rats fed on 20% casein diet in Exp. 2.
