Metabolism of L-Ascorbic Acid-l-14C in Guinea Pigs with Alimentary Cholesterol Atheromatosis

Abstract

A diet containing 0.3% cholesterol fed to guinea pigs for 18 weeks caused an accumulation of cholesterol in blood serum, liver and adrenals, atheromatous changes in coronary arteries and a marked increase in the weight of liver and spleen, in comparison with controls fed the same diet without cholesterol. Ascorbic acid intake was the same in these two groups (10 mg per animal per day, given through a stomach tube). Ascorbic and dehydroascorbic acid concentration in liver and adrenals was not changed in the cholesterol-fed animals, but the total quantity of ascorbic acid in their liver and spleen was substantially higher. Urinary excretion of ascorbic, dehydroascorbic and diketogulonic acids was decreased in this group while oxidation of intraperitoneally administered ascorbic acid-1-14C to 14CO2 remained unaltered. Urinary excretion of 14C was lower in the cholesterol-fed group. Specific activity of ascorbic acid in the tissues of cholesterol-fed guinea pigs was found to be significantly decreased at 96 hours after administration of labeled ascorbic acid compared to that at 48 hours. Guinea pigs with experimental atheromatosis had a significantly larger body pool and a moderately, though significantly, prolonged biological half-life of ascorbic acid. In guinea pigs with dietary cholesterol atheromatosis, an increased ascorbic acid retention exists.