Amino acid levels in hydrazine-treated rats.

Several studies have indicated that hydrazine produces an amino acid imbalance in experimental animals. The early work of Lewis and Izume (1926) suggested a hydrazine block of amino acid utilization since it impaired the ability of glycine to elevate the blood sugar of hypoglycemic rabbits. More recently, Amenta and Johnston (1963) have investigated the ability of liver slices from hydrazine-treated rats to metabolize 14Clabeled amino acids. The ability of liver slices from treated rats to convert glycine or alanine to COZ was impaired by 60-70x. In contrast, the incorporation of labeled amino acids into cellular protein was increased. According to the authors these data suggest a block in amino acid metabolism, but no block in the ability to incorporate amino acid into protein. A number of previous studies with in vitro systems have shown that hydrazine and a number of its derivatives inhibit the conversion of amino acids to keto acids. This inhibition could be reversed by the addition of pyridoxal phosphate to the reaction mixture (Killam and Bain, 1957; McCormick and Snell, 1961). Banks and Stein (1965) have also demonstrated that liver RNA and liver protein are concomitantly elevated in hydrazine-treated rats, thus the authors suggest an in vivo stimulation of liver protein synthesis by hydrazine. Simonsen and Roberts (1967) have published data on the influence of hydrazine on the distribution of free amino acids in mouse liver. Increased levels of alanine, glutamic and aspartic acids, ornithine, glycine, and citrulline were noted in livers of hydrazine-treated rats. The relationship of hydrazine-induced amino acid imbalance to the acute convulsive response to hydrazine is not apparent although elevated levels of y-aminobutyric acid in the brains of animals treated with hydrazine have been reported by Maynert and Kaji (1962). In the present study, plasma and tissue amino acid levels were investigated in hydrazine-treated rats, The effects of hydrazine on the absorption and distribution of a tyrosine load was determined. In addition, the relationship of pyridoxine to the amino acid imbalance produced by hydrazine was investigated.