Flashcards in Liver and Integration of Metabolism Deck (19):
The liver plays an important role in the metabolism of drugs and xenobiotics. Describe how the liver metabolizes drugs and xenobiotics to ensure they will be excreted in the urine
In order for the kidney to eliminate drugs and xenobiotics, the compounds must be made hydrophilic. There is a two phase reaction that takes place in the liver to convert drugs to their hydrophilic form.
Identify the enzyme complex responsible for the oxidation reactions in phase I metabolism of drugs and xenobiotics
Phase 1: The introduction of OH or COOH groups, usually through the oxidation of the parent compound. The enzymes responsible for this are present a an enzyme complex of
NADPH-cytochrome P450 reductase and hemoproteins
aka cytochrome p450
The liver plays an important role in the metabolism of carbohydrates. Identify the major pathways of carbohydrate metabolism that are active in the liver
Glycolysis, glycogenolysis, gluconeogenesis, glycogenesis
Compare the rates of glycogen synthesis and degradation following a period of feeding.
Glycogen synthesis >> glycogen degradation following a period of feeding
Describe insulin's role in regulating hepatic glycogen metabolism and gluconeogensis
Insulin, released when glucose levels are high, stimulates the storage or glucose as glycogen in the liver
Describe glucagon's role in regulating hepatic glycogen metabolism and gluconeogenesis
Glucagon, released when blood glucose levels drop, stimulates gluconeogenesis
Explain the impact of hepatic liver disease on blood glucose levels.
When the liver is damaged, it can not properly regulate blood glucose levels. This leads to hypoglycemia during times of fasting
The liver plays an important role in the metabolism of lipids. Review the role of the liver in lipid metabolism
The liver is responsible for the beta oxidation
Identify the plasma lipoproteins that are synthesized and/or metabolized in the liver
VLDL and HDL are synthesized in the liver
Chylomicron remnants are sent to the liver to deliver CE
IDL and LDL delivers cholesterol to the liver and other cells
The liver produces most of the circulating plasma proteins. Explain why liver disease and long term starvation can result in generalized edema.
Not producing enough proteins in the blood/not enough albumin.
This leads to high hydrostatic pressure (and low oncotic pressure) so fluid leaks out into the interstitium.
Cirrhosis --> portal hypertension --> ascites.
Identify at least four protein that are synthesized predominantly in the liver.
Plasma proteins: albumin
Clotting factors: fibrinogen, prothrombin, transferrin
Where is urea produced?
What happens when the liver can no longer process amino groups into urea?
Hyperammonemia --> brain damage
WHat is the role of the liver in the handling of amino acids
The liver plays an important role in the synthesis and inter-conversion of amino acids.
What type of vitamins are stored in the liver?
Fat soluble vitamins
What metals are stored in the liver?
Iron and copper.
The liver is important in the storage and hemostasis of iron and copper.
What is another name for vitamin A?
What is the major role of the liver in vitamin D handling
Although the major vitamin D stores are in the adipose and skeletal muscle, some is stored in the liver.
The liver is responsible for the initial activation of D3; it converts this form to 25-hydroxycholecalciferol and synthesizes the vitamin D binding protein