The metabolic process in which glucose is formed from non-carbohydrate precursors
Glucose is an essential molecule in the body. It is the most widely used aldohexose in organisms. One of its functions is it serves as an energy source in aerobic respiration, anaerobic respiration, and fermentation. Glucose is oxidized to yield metabolic energy (e.g. ATP) through glycolysis. In the brain, glucose provides almost all of the energy needed in psychological and mental processes.1 Thus, keeping up the appropriate levels of blood glucose is essential.
One of the ways through which blood glucose is provided is through the degradation of glycogen via the process of glycogenolysis. Stored glycogen in the liver cells is broken down into glucose precursors through the process of glycogenolysis.
Another way is through gluconeogenesis. Gluconeogenesis is a metabolic process wherein glucose is generated from non-carbohydrate precursors, e.g. pyruvate, lactate, glycerol, and glucogenic amino acids. Gluconeogenesis seems like the reverse of glycolysis in a way that glucose is converted into pyruvate whereas in gluconeogenesis, pyruvate is converted into glucose.
In humans and many other vertebrates, gluconeogenesis takes place mainly in the liver cells. It often occurs during the periods of fasting, low-carbohydrate diets, or intense exercise. Cytologically, the process begins in the mitochondria then ends in the lumen of the endoplasmic reticulum. Glucose formed from hydrolyzing glucose-6-phosphate by the enzyme glucose-6-phosphatase is then shuttled from the endoplasmic reticulum into the cytoplasm.
Abbreviation / Acronym: GNG
1 Retrieved from http://neuroscience.uth.tmc.edu/s4/chapter11.html