Résumé
1. Experiments were conducted to compare the blood glutathione peroxi-dase activity of rats fed low selenium diets (0.0042 and 0.0084ppm Se) mainly composed of rice, corn and soybean grown in Keshan Disease endemic areas with that of rats fed the contrast diets (0.073 and 0.074 ppm Se) composed of the same grains grown in non-endemic areas and with that of rats fed stock diets (0.307 ppm Se). The enzyme activities of the endemic grain-feeding groups were lower than that of the non-endemic grain-feeding groups, but the enzyme activities of these groups were significantly lower than that of the stock diet group. The difference of the percentage of ascorbic acid-induced oxidation of hemoglobin to methemoglobin, choleglobin and Heinz bodies in vitro in different groups were in the same trend as that of the glutathione peroxidase activity.2. When rats were fed the low selenium diets for three months supplementing with sodium selenite, both the blood selenium levels and glutathione peroxidase activities were increased to the levels of the stock diet group within 50 days.
Résumé
0.05) The above amount was enough to maintain the subjects two weeks in good vitamin C nutrition as judged by steady plasma ascorbic acid content of about 1 mg%. At the end of maintenance period, 400mg of ascorbic acid was administered. The urinary excretion of ascorbic acid in 24 hours was about 30% of the test dose.This method is reliable but not suitable for large scale analysis as it involves daily urine collection and analysis.The urinary excretion of ascorbic acid decreased during menstrual period in women subjects.