GI 20 Flashcards
What roles does the liver play in glucose?
It does, glycogen storage, glycogenolysis, and gluconeogenesis
What is Glycogenesis?
The liver taking up glucose and converting it to Glycogen
What is Glycogenolysis?
When the body needs glucose to meet physical demands so glycogen is broken down into glucose and put into the circulation
What is Gluconeogenesis?
When the liver makes new glucose
What does the liver have a very important role in?
Buffering the blood glucose level
What are the four fates of fatty acids when they come to the liver?
- Storage as triglycerides
- Beta-oxidation (energy production)
- De novo lipogenesis (DNL)
- Lipoprotein secretion
How can fatty acids be used for energy?
Through beta-oxidation in the mitochondria
What is De novo lipogenesis?
Using carbohydrates to make new fat
What is the typical form Lipoprotein secretion by the liver?
Triglycerides in the form of VLDL
What is the issue with the liver storing triglycerides?
Normally it is a natural physiological function but it can become problematic in extreme cases
What is a fatty liver?
When the liver is full of triglycerides
How does increased fat storage impact the liver?
It can impact liver function
What family do hepatocytes express detoxifying enzymes?
P450 family; CYPs
What is the general activity of CYPs?
To detoxify xenobiotics and toxins, primarily through oxidation
What is the most common reaction catalyzed by CYPs?
A mono-oxygenase reaction (incorporation of a hydroxyl group)
What is the purpose of mono-oxygenase reactions?
The addition of the -OH makes the molecule a little bit more polar and a little bit easier to get rid of
What are the main characteristics of CYPs?
- Multiple substrates
- Induced by various compounds
- Inhibited by various compounds
What enzyme will come into effect when an individual is a heavy drinker?
CYP2E1
What does CYP2E1 do?
Takes alcohol (ethanol) and turns it into an acetaldehyde
What process is acetaminophen metabolized by?
Glucuronidation
How does CYP2E1 affect acetaminophen?
In heavy drinkers it gains access to acetaminophen and produce a toxic metabolite that is very damaging for the liver
What is ammonia toxic to?
The central nervous system
What is ammonia generated in the body by?
Amino acid metabolism
What happens to ammonia within the hepatocytes?
It is metabolized to urea and excreted in the urine or feces
