case 5 - storage functions of the liver Flashcards
how much glycogen is stored in the liver
around 100g
describe the steps of the synthesis of glycogen
Glucose is converted to Glucose-6-P by glucokinase (hexokinase in skeletal muscle)
Glucose-6-P is converted to Glucose-1-P by phosphoglucomutase
Glucose-1-P is then converted to UDP-Glucose
Finally UDP-glucose is added to the glycogen chain within the liver either by glycogen synthase or branching enzyme
what are the lipid-soluble vitamins A,D,E,K stored in the liver as
vitamin b12
where is vitamin A stored in the liver and what as
stored in the stellate cells as retinyl ester
what is the active form of retinyl ester
retinol
how is retinol converted to retinyl ester
by lecithin:retinol acyltransferase
what is it called when vitamin D is produced by the body
cholecalciferol
what are the functions of vitamin D
Maintaining normal serum calcium and phosphate concentrations
Increased absorption of calcium in the kidneys and intestines
Increased mobilisation of calcium from bone , activating osteoclasts to release more calcium
where can vitamin E be stored
in the liver or adipose tissue
what are the function of vitamin E
antioxidant
preventing the propagation of free radicals
protects vitamin A
what are the function of vitamin K
Important for synthesis of clotting factors II, VII, IX and X.
Co-factor for enzymes
what is another name for vitamin B12
cobalamin
what are the functions of vitamin B12
Production of DNA and RNA
Maintaining healthy neurones
Red blood cell production – alongside Vitamin B9
what minerals are stored in the liver
iron and copper
what is most iron stored within the cells as
ferritin