Spectrophotometric Analysis of Tyrosine,Tryptophane and Nucleic Acids in the Plasma of Rats Treated with p-Dimethylaminoazobenzene

Abstract

Tyrosine, tryptophane and nucleic acids content were determined by U.V. spectrophotometric method in plasma samples taken at the level of the posterior vena cava and of the vena hepatica of normal, control (Cantero diet), treated (Cantero diet + DAB), and hepatoma-bearing rats of both sexes. Modifications of the tyrosine values were observed only in female rats: the amino acid was decreased in the controls and in the treated rats, whereas in hepatoma-bearing rats its values returned to normal. Unrelevant modifications were observed for tryptophane values, which, however, tended to decrease in males and females of the control, treated, and hepatoma-bearing groups. Nucleic acids were diminished in the female and male rats of the control group and increased, particularly in the peripheral plasma, in DAB-treated or hepatoma-bearing animals of both sexes. Previous studies carried out by the authors, under the same experimental conditions, pointed out a divergence between nitrogen content (determination with Kjeldahl's method) and extinction at wave lengths of maximum and minimum absorption, determined with U.V. spectrophotometry in the peripheral and suprahepatic plasma: this observation may be now interpreted on the basis of the above results.