Glycogen stores

Figure 6. Glycogen content in the vastus lateralis muscle as a function of cycling time at 75-80% of maximal oxygen uptake (VO2 max). Data points are mean values from 10 subjects. For each subject, exercise was performed repeatedly in periods of 15 min separated by 15 min rest periods. At the point of exhaustion and muscle fatigue, muscle glycogen stores were depleted. From Bergstrom and Hultman (1967) with permission from the publisher.

Figure 10. The relationship between the initial glycogen content in vastus lateralis muscle and work time in six subjects who cycled to exhaustion at 75% VO2 max. Each subject cycled to exhaustion on three occasions. The first experiment was preceded by a mixed diet (a), the second by a carbohydrate-poor diet (o), and the third by a carbohydrate-rich diet ( ). The energy contents of the diets were identical. In all experiments depletion of the muscle glycogen store coincided with exhaustion and muscle fatigue. From Bergstrom et al. (1967) with permission from the publisher.

Glycogen storing Liver Yellow perch No Increased Hontela et al. 

The main source of brain energy metabolism is the continuous availability of glucose from the blood. To some extent, energy can be derived from glycogen, stored in astrocytes. Neurons also use lactate as an energy source, even under normoxic conditions. During neuronal activation, lactate may even be the... 

The anaerobic metabolism of adult body wall muscle has been well characterized (Komuniecki and Harris, 1995). Large glycogen stores are... 

Rosenvold K, Petersen J S, Lrerke R N, Jensen S K, Therkildsen M, Karlsson AF1, Moller R S and Andersen H J (2001), Muscle glycogen stores and meat quality as affected by strategic finishing feeding of slaughter pigs , J Anim Sci, 79, 382-391. 

No ATP is required to remove glucose from glycogen stores. Degradation 1... 

Glycogen is basically a short-term supply. In the absence of food intake, glycogen stores are depleted in about 24 hours. Over longer periods of fasting or starvation, glucose equivalents cannot be provided by glycogen stores and must come from protein sources. 

Glycogen stores in liver and kidney are exhausted in about 24 hours. After this, the body must find glucose equivalents somewhere. The major metabolic adaptations of starvation are the result of having to maintain glucose levels without any direct source of it (Fig. 17-8). 

The polymorph is the dominant white cell in the blood stream and, like the macrophage, shares a common hemopoietic stem cell precursor with the other formed elements of the blood. It has no mitochondria, but utilizes its abundant cytoplasmic glycogen stores for its energy requirements thus, glycolysis enables these cells to function under anaerobic conditions such as those in an inflammatory focus. It is a nondividing, short-lived cell with a segmented nucleus. 

---