Influence of partial starvation and of acute scurvy on the free amino acids in blood plasma and muscle in the guinea-pig.

Various investigators have reported changes in the concentration of the free amino acids in blood plasma and tissues of guinea-pigs in acute vitamin C deficiency. Christensen & Lynch (1948) found in guinea-pigs deficient in ascorbic acid a large decrease in the glycine and glutamine contents of skeletal muscle and in the glutamine content of the liver. Levels of amino acids other than glycine and glutamine, determined as non-glutamine a-amino nitrogen, tended to be elevated in the liver, in plasma and especially in muscle. Guinea-pigs restricted in food intake did not show significant changes in glycine and glutamine distribution. Ginter (1957) studied the free amino acids of the skeletal muscle of guinea-pigs deprived of ascorbic acid. He found an increase in the glutamic acid level and the valine-methionine and leucine fractions, and a reduction in the level of glutamine and aspartic acid. By comparison of the amino acid content of blood plasma in ascorbic acid-deficient and normal guinea-pigs, Rangneker & Dugal (1958) found that in the former arginine, threonine, hydroxyproline and cystine were absent and the levels of leucine, valine, alanine, glutamic acid, serine and glycine were lower than in normal animals. On the other hand, the levels of phenylalanine, lysine and histidine were higher. The results of Ginter (1957) and Rangneker & Dugal(1958) were obtained by the technique of paper chromatography. The development of the Moore & Stein (1954) technique for amino acid analysis gave us the opportunity to carry out a systematic study of the free amino acids of blood plasma and muscle tissue in the guinea-pig and to test former observations. Our studies indicated that the majority of the changes in the concentration of free amino acids in the tissues of animals with experimental scurvy are not specific for ascorbic acid deficiency, the findings not deviating essentially from those observed with guinea-pigs subjected to partial starvation.