metabolic zone of liver
Any of the metabolic zones found in the liver. Liver tissue is heterogenous at the level of morphometry and histochemistry. This heterogeneity is linked to the position of a cell within the functional unit of the tissue, which, in turn, is related to the blood supply: cells located in the upstream zone differ from those in the downstream zone with respect to subcellular structures, key enzymes, translocators, and receptors and, therefore, have different metabolic capacities. This is the basis for 'metabolic zonation', a concept first proposed in mammals for carbohydrate metabolism and later expanded to include amino acid and ammonia metabolism, xenobiotic metabolism, protective metabolism, and formation of plasma proteins.