Liver glycogen stores

Figure 16.8 Pattern of fuel mobitisatton and utUisatton during early starvation. This is starvation over a period of about 24 hours liver glycogen stores are nearly depleted and fatty acid mobilisation is taking place.

This phase is entered with the depletion of liver glycogen stores and is characterised by two important metabolic features ... 

B) Liver glycogen stores are only partially depleted, due to an increase in gluconeogenesis... 

After about 30 hours, when liver glycogen stores are depleted, gluco-A neogenesis becomes the only source of blood glucose. 

Intra-uterine growth retardation. Small-for-dates babies may have inadequate liver glycogen stores. This situation is further compromi/cd by prematurity because glycogen is laid down mainly in the last four weeks of pregnancy. 

The neonate must rapidly adapt to an intermittent fuel supply after birth. Once the umbilical cord is clamped, the supply of glucose from the maternal circulation is interrupted. The combined effect of epinephrine and glucagon on the liver glycogen stores of the neonate rapidly restore glucose levels to normal. 

Fig. 28.2. Glycogenolysis in skeletal muscle and liver. Glycogen stores serve different functions in muscle cells and liver. In the muscle and most other cell types, glycogen stores serve as a fuel source for the generation of ATP. In the liver, glycogen stores serve as a source of blood glucose.

In the neonate, the release of epinephrine during labor and birth normally contributes to restoring blood glucose levels. Unfortunately, Getta Carbo did not have adequate liver glycogen stores to support a rise in her blood glucose levels. 

By 30 hours after a meal, liver glycogen stores are substantially depleted. Sub-sequendy, gluconeogenesis is the primary source of blood glucose. 

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