Gluconeogenesis (GNG) is a chemical process inliving bodies. In gluconeogenesis, the body turnsfats andproteins (glucogenic amino acids) intosugars calledglucose.[1] In mostanimals with spines, gluconeogenesis happens in theliver, but some animals have gluconeogenesis in thekidneys.[2] gluconeogenesis usually happens when the organism has not eaten manystarches or sugars or eatennothing at all for a long time. Not eating and not eating starch can causeketosis, which is when some cells useketones for fuel.[3]
In humans, the main gluconeogenic compounds arelactate,glycerol (a part of thetriglyceridemolecule),alanine andglutamine. They are involved in over 90% of the overall process.[5]
Lactate comes back to the liver where it is converted intopyruvate by theCori cycle using the enzymelactate dehydrogenase. Pyruvate, the first designatedsubstrate of the gluconeogenic pathway, can then be used to make glucose.[6]
Fat is mostly broken down, but if there is no fat to break down, or the body cannot access the fat stores, then proteins found in themuscle can break down, resulting in muscle loss.[7]
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