Abstract
It was previously reported that methionine and threonine supplementation to a protein free diet had a greater nitrogen sparing effect than methionine supplementation along. The reduced urinary nitrogen excretion by methionine and threonine is due to the reduced excretion of urea. In the present study, the changes in tissue level of free amino acids and ammonia were investigated. Ornithine is one of the urea cycle inter-mediates and may play an important role for urea formation, therefore the liver concentration of ornithine was also determined. The contents of ammonia in plasma were the same in these two groups and the ammonia content in liver of rats fed the control diet was smaller than that of rats fed the protein free diet supplemented with methionine and threonine. The contents of some amino acids in tissues were significantly reduced. The concentrations of aspartic acid, glutamic acid, alanine and serine in plasma and liver of rats fed the protein free diet supplemented with methionine and threonine were, particularly, significantly reduced as compared with those of rats fed the protein free diet. In addition to the decrease of free amino acids which are considered to be nonspecific nitrogen carriers from the peripheral tissues, the concentration of ornithine in liver was also significantly reduced. The results suggest that the decreased migration of free amino acids from peripheral tissues to the decreased level of liver ornithine would efficiently reduce the urea formation in rats fed the protein free diet supplemented with methionine and threonine.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.