The hepatic glycogenoreticular system.

One of the major liver functions is the ability of hepatocytes to store glucose in the form of glycogen for various purposes. Beside glucose production and secretion, the synthesis of glucuronides and ascorbate has been reported to be dependent on the extent of the glycogen stores and on the rate of glycogenolysis in the liver. It is common that the final steps of these pathways are catalysed by intraluminally orientated enzymes of the endoplasmic reticulum, which are supported by transporters for the permeation of substrates and products. On the basis of the close morphological and functional proximity of glycogen, glycogen-dependent pathways and the (smooth) endoplasmic reticulum we propose to use the term glycogenoreticular system for the description of this export-orientated hepatocyte-specific metabolic unit.