Diabetes in dogs preventor of the breakdown or catabolism of glycogen and fat. The absence of sufficient insulin causes this breaking-down process to be accelerated; it is the mechanism behind metabolizing fat instead of glucose and the appearance of ketones. Since the glucose that normally enters the cells is unable to do so without insulin, it begins to build up in the blood where it can be seen as hyperglycemia or high blood glucose levels. The tubules of the kidneys are normally able to re-absorb glucose, but they are unable to handle and process the amount of glucose they are being presented with.
Glycogen storage disease type 0 liver provides a steady source of glucose from glycogen breakdown (or glycogenolysis). With prolonged fasting, glucose is generated in the liver from noncarbohydrate precursors through gluconeogenesis. Such precursors include alanine (derived from the breakdown of proteins in skeletal muscle) and glycerol (derived from the breakdown of triacylglycerols in fat cells). In patients with glycogen-storage disease type 0, fasting hypoglycemia occurs within a few hours after a meal because of the limited stores of hepatic glycogen and inadequate gluconeogenesis to maintain normoglycemia. Feeding characteristically results in postprandial hyperglycemia and glucosuria, in addition to increased blood lactate levels, because glycogen synthesis is