Metabolism of ammonia under some environmental conditions

Previous work in this series has shown an increase in the ammonia content of the brain, liver and blood under the noisy condition. The ammonia levels in the tissues will depend on the metabolic equilibrium between its production and its removal.Therefore, in order to determine whether the increase in the ammonia content was brought about by the acceleration in its production or by the disturbance in its removal, this study was undertaken.For the observation of the production of ammonia, the untreated rat's brain or live homogenate boiled at 100°C for 5 minutes, or 2mM glutatoione solution were used as the source of ammonia.For the observation of the disturbance in the removal process, 2mM ammonium chloride solution was used as the substrate.The adult male rats were exposed to noise, as previously mentioned. The brain and liver homogenate from these rats were added to the above-mentioned substrates. The reaction mixtures were inbubated at 37°C for 1 hour, and then the ammonia content of these mixtures were estimated.Results were as follows:a) In the ability for the production of ammonia in the brain and liver, there was no significant difference between the noise-exposed and the control animals.b) The ability for the removal of ammonia in the brain and liver of the noise-exposed animals was lower than that of the control ones.c) By the addition of ammonium chloride plus glutamic acid or aspartic acid to the tissue homogenates from the noise group, the ability for the removal of ammonia in the brain was still disturbed, but in the liver it returned to the control value approximately.It may be concluded from the results of this investigation that the increase in the ammonia content in the brain and liver under the noise condition was brought about mainly by the disturbance in the removal process.