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Urea synthesis in the liver, and potentially fatal hyperammonaemia in a child

Objectives

At the end of the session you should be able to:

Explain the catalytic effect of adding arginine, and other metabolites on the rate of urea synthesis from ammonium in liver, and describe the pathway of urea synthesis

Describe the main pathways of ammonium formation in liver and its incorporation into urea

Explain the importance of N-acetylglutamate in urea synthesis

Explain how supplements of arginine are beneficial in the treatment of hyperammonaemia associated with argininosuccinic aciduria

Describe the enterohepatic circulation of urea

 

In this exercise you will repeat the experiments performed by Krebs and Henseleit in 1932, when they first elucidated the pathway of urea synthesis. Two essays by Krebs on the thought processes involved in their studies are of interest:

Krebs HA, 1973, BIochemical Education 1:2, 19-23. Available at http://www.sciencedirect.com/science/article/pii/0307441273900484, but you need a subscription

Krebs HA, 1982, Trends in Biochemical Sciences 7:2, 76-78. Available at http://www.sciencedirect.com/science/article/pii/0968000482900834, but you need a subscription

Start this exercise