10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 2 2013 (April - June) Ammonia is not just a waste product of nitrogen metabolism but involved for the synthesis of many compounds in the body like aminoacids, purines, pyrimidines, aminosugars, asparagines etc. Excess ammonia is excreted mainly as urea which is synthesized in the liver through urea cycle. Ammonia is a normal constituent of all body fluids but can become a toxicant under ammonia stress which leads to ammonia toxicity or Hyperammonemia. In this condition metabolic mechanisms are disturbed. The present study aims to examine the changes in biochemical parameters under ammonia stress. The LD50 of ammoniumsulphate after toxicity evaluation was 91.5mg/kg body weight. The sub lethal dose i.e1/5 of LD lessThan sub greaterThan 50 lessThan /sub greaterThan , which is 18.3mg of ammoniumsulphate /kg body weight, was injected intraperitonially to rats for one week treatment. The selected biochemical parameters like Total proteins, Soluble proteins, Structural proteins, Free amino acids and Proteases levels were estimated in Liver and Brain tissues of Albino rats by using standard methods. The changes in these biochemical components under ammonia stress will be discussed. A. SHOBHA RANI AND P. NEERAJA Ammonia stress, Total Proteins, Soluble and Structural Proteins, Free aminoacids, Proteases. 73-78