Synthesis of glucose from non-carbohydrate precursors such as:
Alcohol metabolism by the liver inhibits gluconeogenesis. In conditions where glycogen stores are low (eg following strenuous exercise or undernourishment) alcohol consumption can result in hypoglycaemia because of the combined decrease in gluconeogenesis and glycogenolysis.
The effects are particularly severe in insulin-treated diabetics who already have a tendency to hypoglycaemia.
A storage form of carbohydrate
Found predominantly in liver and muscle
Liver glycogen acts as a rapidly releasable glucose reservoir that is used to regulate the blood glucose concentration.
Muscle glycogen provides a local supply of glucose during exercise.
Glycogen storage diseases are caused by inherited deficiencies of enzymes involved in glycogen synthesis or breakdown. The clinical features are determined by the particular enzyme affected. Two major types are von Gierke's disease and McArdle's disease.
Deficiency of glucose-6-phosphatase, major enzyme for releasing free glucose from glucose-6-phosphate in the liver. Massive hepatomegaly and fasting hypoglycaemia develop, because liver glycogen cannot be mobilised under conditions of starvation.
Deficiency of muscle phosphorylase => cannot mobilise muscle glycogen Featured by impaired exercise tolerance and accumulate glycogen in muscle tissue