Effect of increasing storage iron on ascorbic acid metabolism in the guinea pig

Ascorbic acid (AA) metabolism was studied in control and iron-loaded guinea pigs. All animals were fed an AA-deficient diet and given a daily intraperitoneal (ip) dose of 10 mg sodium ascorbate. The control-diet formula contained 0.10 g Fe/kg diet; the experimental diet contained an additional 3.33 g Fe/kg diet as FeSO4. After 14 wk animals were injected (ip) with 9.25 x 10(3) Bq [1-14C]L-ascorbic acid. Blood was collected for 10 d and plasma specific activity of AA was determined. All animals were subsequently killed and selected tissues were analyzed for AA and iron concentrations. In spite of marked elevation of iron concentrations in plasma, spleen, and liver in experimental animals compared with controls, no differences in AA metabolism as determined by tissue AA concentrations and AA half-life, turnover rate, and body-pool size were evident. These results demonstrate that iron loading has no effect on the rate of AA catabolism in guinea pigs.