End Product Nitrogen Metabolism

Nitrogen metabolism is a complex biochemical function that must be controlled to prevent toxicological consequences. Amino acid degradation results in formation of ammonia. Ammonia excess must be removed as urea. Numerous diseases exist within the nitrogen excretion pathways. Liver failure and genetic disorders of metabolism result in the accumulation of ammonia or other metabolites.

Metabolic Solutions can help you apply stable isotope techniques for end product nitrogen metabolism studies. We are helping clients determine ammonia nitrogen metabolism using 15N-lactose ureide, evaluate interventions in amino acid disorders such as phenylketonuria, determine ureagenesis, and evaluate nitrate biosynthesis following probiotic treatment.

List of End Product Nitrogen Metabolism Services

  • Measurement of 15N-total nitrgen, 15N-ammonia and 15N-urea
  • D5-phenylalanine, hippuric acid, trans cinnamic acid, and phenylpyruvate
  • 13C-urea and 15N-urea to determine ureagenesis
  • Nitrate synthesis using 15N-ammonia or 15N-arginine

Ammonia Nitrogen Metabolism (15N-lactose ureide tracer)

Metabolic Solutions can analyze colonic nitrogen metabolism experiments using 15N-lactose ureide during probiotic treatment interventions. These studies can help you evaluate nitrogen uptake by bacteria. When 15N-lactose ureide reaches the colon, it is metabolized to 115N-urea by bacteria. The 15N-urea is rapidly converted to 15N-ammonia. The observed changes in 15N levels reflect the fate of total colonic ammonia.

Amino Acid Genetic Disorders (Deuterium or 13C Labeled Amino Acid Tracers)

Our expertise includes measurements of amino acid disorders with stable isotopes. For example, ring D5-phenylalanine can be given to subjects and the measurement of phenylalanine metabolites such as hippuric acid, trans cinnamic acid, and phenylpyruvate can be measured in plasma and urine by LC/MS/MS.

Ureagenesis (13C-acetate or 15N-ammonia Tracers)

Urea cycle activity can be monitored by 13C-acetate or 15N-ammonia tracers. In these experiments, the tracer is given orally. Blood is collected over 4 hours. Determination of urea concentration and labeled urea over time can be used to determine ureagenesis. Interventions to treat urea cycle disorders can be investigated using this approach.

Nitrate Synthesis (15N Precursors)

Formation of nitrate can be used as a biomarker for probiotic treatment studies or during pathological conditions. 15N-labeled precursors such as ammonium acetate or arginine can be utilized to detect nitrate formation.