Effect of massive doses of ascorbic acid on its catabolism in guinea pigs
Hornig, D.; Weiser, H.; Weber, F.; Wiss, O.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 43(1): 28-33
1973
ISSN/ISBN: 0300-9831 PMID: 4696819 Document Number: 57636
Male guineapigs were given for 3 weeks a basal diet free of vitamin C with ascorbic acid added at 0.2, 1.0, 5.0 and 25.0 g/kg diet, giving intakes of about 4, 20, 100 and 500 mg/day. At the end of that time mean plasma vitamin C concentrations (no value for the 5 mg/kg diet) were 0.14, 0.48 and 0.53 mg/100 ml. Feed was withheld for 12 to 15 h and each animal was given an emulsified feed containing 10 mu Ci ascorbic acid-1-14C and placed in a metabolism chamber for 8 or 24 h with free access to feed and water. Hourly rate of respiratory output of 14CO2 reached a peak after 4 h and had almost ceased by 8 h. No significant difference in respiratory or urinary excretion of the label could be associated with previous intake of the vitamin. Hence high intakes of ascorbic acid for 3 weeks had no inducing effect on the enzyme systems metabolizing the vitamin.