The liver is an amazing organ when it is working properly. It is the largest and heaviest internal organ. According to
wikipedia--a fantastic source of medical information, I know, especially to all of the medical and lab professionals out there--it is thought to be responsible for ~500 separate functions in the body. It is important in many types of protein synthesis, all sorts of metabolic cycles (e.g. carbohydrates and lipids), produces blood coagulation factors, stores such substances like vitamin D and iron, and breaks down toxic substances (many of you know that about drinking alcohol, for example).
Bottom line: when you have a failing liver, you will have a lot of different problems to look forward to.
It was clear a few years ago that Dad started to have trouble breaking down toxic substances. Again, Dad never really drank, so this is not an issue about alcohol. Or drugs--he doesn't do that either. The liver plays a key role in converting ammonia to urea. Ammonia (NH3) is the product of
oxidative deamidation reactions. The reaction is part of the breakdown process of amino acids (they are the building blocks of proteins, for the non-scientists). To humans, ammonia is toxic even in small amounts. In a healthy person, ammonia is converted to urea via the
urea cycle and then excreted from the kidneys. When someone has end-stage liver disease, they could potentially have a build-up of ammonia levels. This is not good.