Gluconeogenesis Flashcards
what level is the most potent promoter of glycolysis or gluconeogenesis
Blood glucose (bg) level
what occurs in the fed state (after eating)
Decrease in glucagon
Increase in insulin, glycolysis, glycogen synthesis, amino acid synthesis, fatty acid synthesis
what occurs in the fasted state
decrease insulin
increase glucagon, fatty acid oxidation, amino acid breakdown, gluconeogenesis, glycogenolysis
how many calories worth of energy does the body store as glycogen
2000
What is Gluconeogenesis
Synthesis of glucose from non-carbohydrate precursors (pyruvate, lactate, glycerol
what does gluconeogenesis maintain
maintenance of blood glucose levels during starvation or vigorous exercise
where does gluconegensis occur
mainly in the liver and to a lesser extent in the kidney
what makes up glucose
60% Certain AA – degradation of muscle protein
28% Lactate – from anaerobic glycolysis in exercising muscle “Cori cycle”
12% Glycerol – breakdown of triacylglycerol in adipose
what are the 3 irreversible enzymes of glycolysis
Hexokinase (1) converts glucose to glucose 6-phosphate
Phosphofructokinase (2). converts fructose 6-phosphate to fructose-1,6-bisphosphate
Pyruvate kinase (3) converts phosphoenolpyruvate to pyruvate
what can any metabolite be converted into
pyruvate or oxaloacetate
what does the conversion of lactate to glucose require
energy which is derived from the oxidation of fatty acids in the liver.
where does glucose produced by the liver enter
the bloodstream for delivery to peripheral tissues and the cori cycle
what is the Cori cycle
Metabolism under conditions of vigorous exercise (limited oxygen)
represents the transfer of chemical potential energy in the form of glucose from the liver to peripheral tissues
what enzymes aren’t cytosolic
Glucose 6-phosphatase - ER
Pyruvate carboxylase - mitochondria
PEP carboxykinase - cytosolic and mitochondrial
where is oxaloacetate produced
mitochondria
