Studies on Reduced Ascorbic Acid Content of the Blood Plasma.

Abstract

Recently Farmer and Abt' described a method for the determination of the reduced ascorbic acid in the blood plasma. Briefly, the procedure consists in deproteinizing the blood plasma with tungstic acid and titration with 2 :6 dichlorphenolindophenol. They reported that the values obtained by this method parallel the intake of vitamin C and are an accurate index of the nutritional state relative to vitamin C. We have made many determinations of the reduced ascorbic acid in the blood plasma using essentially the technique of Farmer and Abt. We find it rapid and reliable and our data lead us to concur with their opinion of its significance.It is the purpose of this communication to present briefly some of our own studies which indicate that the plasma level of reduced ascorbic acid is an accurate index of the immediate nutritive level with regard to vitamin C and in health parallels the intake of the vitamin. Equally convincing data in studies of rheumatic fever and rheumatoid arthritis is reported separately. With very few exceptions our study is based upon p s t absorptive blood specimens. All data presented refer to the ascorbic acid in the blood plasma present in the reduced form.Iizfiuence of Simll a i d Large Doses of L'itnilziiz C upon Plasma Lcwls. The plasma ascorbic acid levels of 7 apparently normal adults were determined before and after ingestion of 6 oz. of orange juice. The results, which are summarized in Table I, show an appreciable rise of the plasma level 2 to 4% hours after the administration of this relatively small dose of vitamin C. The increases ranged from 15% to 69%. For this reason we believe that fasting blood specimens are essential for comparative data.In Fig. 1, the plasma ascorbic acid curves of 4 individuals who received large doses of ascorbic acid (0.5 ,om. per 100 lb.) are shown. The curves are similar in type to those for blood sugar with ~ * This work was aided by a donation from the California Fruit Growers Ex-We are indebted IFarmer, C. J., and Abt, A. F., PROC. SOC. EXP. BIOL. AND MED., 1935, 32, change and by tlie Christine Breon Fund for Medical Research.to Roffmann-La Roche, Inc., for supplies of ascorbic acid.

Vitamin C Content of Monkey Tissues in Experimental Poliomyelitis

“…There is well documented evidence to show that species of the first category, such as rats, rabbits, dogs, cats, and cattle, carry higher C levels in all tissues than man and the guinea pig, which belong to the second category (6). Although the monkey's susceptibility to experimental scurvy is well established, figures relating to the C content of monkey tissues, with the exception of the blood (7), have been wanting. The results of our titrations show that the C levels of the monkey fail in line with those of other non-synthesizing species.…”

Distribution of Ascorbic Acid in the Blood and Its Nutritional Significance

“…values between 0.8 and 1.4 mgm. per 100 cc., indicate, according to present knowledge, satisfactory nutrition (4), low plasma concentrations do not provide a reliable index of either deficiency or unsaturation (1,4,5). Van Eekelen, Emmerie and Wolff (6), Neuweiler (7) and Heinemann (8) have presented evidence that whole blood concentrations, which include the ascorbic acid content of the blood cells as well as the plasma, reflect vitamin C nutrition to a greater extent than do plasma concentrations and actually indicate the degree of saturation or depletion.…”

The Distribution of Ascorbic Acid Between Cells and Serum in Relation to Its Urinary Excretion

“…Determinations of the concentration of ascorbic acid in whole blood (1,2,3,4,5,6,7,8) and in plasma or serum (9,10,11,12,13,14,15,16,17,18) as well are believed to indicate the degree of saturation of the organism. No strict correlation, however, has been established between the ascorbic acid content of whole blood and of plasma, although the concentration in cells is consistently higher than in plasma under ordinary conditions (5).…”