Metabolism
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Urea synthesis in the liver, and potentially fatal hyperammonaemia in a child
Studies with isolated hepatocytes
Krebs
and Henseleit used very thin slices of liver, approximately one cell thick,
for their studies. The results here are from more recent experiments using isolated
liver parenchymal cells (hepatocytes).
Isolated hepatocytes provide an extremely convenient
system for metabolic investigations. The isolated cells are prepared by perfusion
of the liver in situ with collagenase; as the collagen in connective
tissue is hydrolysed, so the cells can be separated by gentle pressure, and
suspended in buffer for incubation. A relatively large number of experiments
can be performed using the cells from the liver of each rat or mouse.
The main urinary
nitrogen metabolite in mammals is urea.
What is the main factor that determines how much urea is synthesised and excreted?