Glucose metabolism of gingiva – a review

Hundreds of reactions simultaneously take place in a living cell, in a well-organized and integrated manner. The entire spectrum of chemical reactions, occurring in the living system are collectively referred to as metabolism. Carbohydrate metabolism is a fundamental biochemical process that ensures a constant supply of energy to living cells. The most important carbohydrate is glucose, which can be broken down via glycolysis, enter into the Kreb's cycle and oxidative phosphorylation to generate ATP. A metabolic pathway constitutes a series of enzymatic reactions to produce specific products. As such, the metabolic pathways occur in specific locations (mitochondria, microsomes etc.) and are controlled by different regulatory signals. Cytoplasmic organelle concentration varies among different epithelial strata. Mitochondria are more numerous in deeper strata and decrease toward the surface of the cell.

Glycogen can accumulate intracellularly when it is not completely degraded by any of the glycolytic pathways. Thus, its concentration in normal gingiva is inversely related to the degree of keratinization and inflammation. The hexose monophosphate-shunt mechanism, the Embden-Meyerhof glycolysis scheme, citric acid cycle, mitochondrial terminal electron transport, and oxidative phosphorylation have been identified in gingiva and their relative activities are given in the above order. Glucose metabolism is impaired in uncontrolled diabetes in human oral mucosa. The neutrophil function may be impaired due to reduced glucose-6-phosphate dehydrogenase (G6PDH) activity. Neutrophils kills bacteria by building an oxidative burst. The respiratory burst requires the formation of NADPH. In neutrophils, pentose phosphate pathway is responsible for the formation of NADPH and ribose-5-phosphate for fatty acid and nucleotide synthesis, respectively.