Changes

==Description==

==Description==

'''Ammonia''' is a by-product of protein degradation which is transported in the portal vein and metabolised to urea in the liver via the urea cycle.  Some ammonia is also used in the synthesis of glutamine.    Ammonia is generated in normal animals through the following physiological processes:

'''Ammonia''' is a by-product of protein degradation which is transported in the portal vein and metabolised to urea in the liver via the urea cycle.  Some ammonia is also used in the synthesis of glutamine.    Ammonia is generated in healthy animals through the following physiological processes:

*Hepatic catabolism of body proteins and of proteins absorbed from the gut, including those obtained after gastro-intestinal haemorrhage.

*Hepatic catabolism of body proteins and of proteins absorbed from the gut, including those obtained after gastro-intestinal haemorrhage.

*Metabolism of glutamine by enterocytes of the small intestine, the source of 25% of the energy used by these cells.

*Metabolism of glutamine by enterocytes of the small intestine, the source of 25% of the energy used by these cells.