The document discusses amino acid catabolism and the relationships between organs in metabolizing and transporting amino acids and nitrogen. The intestine absorbs amino acids from food and releases byproducts like ammonium and alanine. The liver synthesizes proteins, breaks down amino acids, and performs gluconeogenesis and urea synthesis. Skeletal muscle breaks down branched chain amino acids and transports amino groups as alanine and glutamine to other organs. One clinical case describes a infant with high blood ammonium levels due to a genetic deficiency in ornithine transcarbamoylase, an enzyme in the urea cycle. Treatment with essential amino acids and sodium benzoate helped reduce ammonium levels.