Gluconeogenesis is the metabolic process through which glucose is synthesized from non-carbohydrate precursors, primarily in the liver and, to a lesser extent, in the kidneys. This pathway is crucial for maintaining blood glucose levels during fasting or intense exercise when carbohydrate stores are depleted. Key substrates for gluconeogenesis include lactate, glycerol, and amino acids. The process is essentially the reverse of glycolysis, involving specific enzymes to bypass irreversible steps.