Effects of ascorbic acid deficiency and of erythorbic acid on blood components in the Cynomolgus monkey.

Eight male Cynomolgus monkeys were fed an ascorbic acid-free total liquid diet until plasma levels decreased from a mean of 1.1 mg/dl to 0.04 mg/dl at 8 weeks. They showed no visible signs of scurvy. The animals were then given a daily oral dose of 10 mg ascorbic acid/kg body weight for 4 weeks, when the experiment was ended. Four of the animals were given, in addition, 200 mg erythorbic acid/kg body weight orally each day. In all animals repletion was accomplished in two to three weeks using return to initial plasma ascorbic acid levels as the criterion. During deficiency, blood cellular elements were found to be more resistant to depletion than plasma. For erythrocytes, this may be explained at least partially by the observation that in vitro uptake of ascorbic acid tended to be related inversely to blood ascorbic acid levels. However, no such relationship was seen in leucocytes or platelets. Other measurements made on blood did not vary in response to changing ascorbic acid levels. These include serum cholesterol; erythrocyte, leucocyte, or platelet counts; leucocyte differential; hemoglobin concentration; and hematocrit. Urinary hydroxyproline/creatinine ratios were also unchanged. Erythorbic acid, a stereoisomer of ascorbic acid and a common food additive, has been cited as a possible interferent in the determination of whole blood or plasma ascorbic acid, since in the guinea pig it is absorbed from the gut and no commonly used ascorbic acid analysis can distinguish between the isomers. Under conditions of the present experiment, however, no elevation of apparent whole blood or plasma ascorbic acid was produced by inclusion of high levels of erythorbic acid in the diet. Animals given erythorbic acid in addition to ascorbic acid during repletion did not differ from those given ascorbic acid alone in any aspect mentioned above.