Glycogen depletion

Broberg, S., and Sahlin, K. (1988). Hyperaramoniemia during prolonged exercise an effect of glycogen depletions J. Appi. Physiol. 65, 2475-2477. 

Costill, D.L., Gollnick, P.D., Jansson, E.D., Saltin, B., Stein, E.M. (1973). Glycogen depletion pattern in human muscle fibers during distance running. Acta Physiol. Scand. 89, 374—383. 

The effects of ROM on liver have already been discussed. The potential involvement of ROM in I/R injury is suggested by the finding that glycogen-depleted livers are more susceptible to ischaemic injury. This is thought to be related to accumulation of hypoxanthine during anaerobic metabolism, which serves as a substrate for XO and hence enhanced production of RDM (Younes and Strubelt, 1988). 

Some researchers reject the explanation that caffeine inhibits glycogen depletion during short term exercise54 but there is an increasing abundance of research supporting the notion of variable sensitivity to caffeine by muscle type. Muscles with higher ratios of type I fibers appear more sensitive than type II fibers, both in animal55-56 and human models.57... 

During product development, many of the initial non-clinical studies were undertaken in GAA knockout mice (i.e. mice devoid of a functional GAA gene), which serves as an animal model for Pompe s disease. The mice proved useful in assessing the pharmacodynamic effect of Myozyme on glycogen depletion and helped establish appropriate dosage regimens. The mice were also used to evaluate pharmacokinetics and biodistribution of GAA following its administration at clinically relevant doses. 

BaP alone produced glycogen depletion in liver cadmium alone caused hepatic perivascular fibrosis. Mixture produced complete disorganization of the hepatic parenchyma, including nuclear degeneration higher increase in EROD activity (by 19-fold), BaP hydroxylase activity (by 71-fold), and cytochrome P-450 microsomal content by 2-fold... 

Answer C. Glycogen depleted around 18 hours, gluconeogenesis from protein begins to drop gradually, and by two weeks, ketones have become the more important fuel for the brain. 

This requirement, however, conflicted with that of achieving a maximum exercise performance, fortoperform many hours of work each day, the diet should have been high in carbohydrate. This is because manhauling, despite being of fairly low intensity in exercise physiological terms, would still lead to marked muscle glycogen depletion in 10 to 12 hours of exertion daily. 

Single dose results in early hepatic glycogen depletion and elevation in blood glucose (Nishimura 1984)... 

Rat (albino) 9 mo (F) Hepatic 50 (increased liver weight, morphological changes in bile ducts, lipid filled lysosomes, glycogen depletion, induction of peroxisomal enzymes and cytochrome P-450 system) Mitchell et al. 1985b... 

Dieldrin CNS effects (tremors convulsions, coma), nausea, vomiting Carcinogen (animal positive), liver damage (glycogen depletion, fatty infiltration, necrosis), kidney damage (fatty changes, necrosis)... 

Figure 4 - Glycogen depletion from the quadraceps femoris during exercise. Data from Essen (15).

As noted previously, like skeletal muscle, glycogen depletion in liver during endurance exercise is much less in trained animals and in animals who have had free fatty acids artificially elevated. No evidence exists that the mechanism proposed by Randle to account for the inhibition of carbohydrate metabolism in muscle by oxidation of fatty acids is operative in the liver. Thus other factors must be responsible for the slower rate of liver glycogen depletion in these situations. Such factors may include a smaller increase in catecholamine levels, a smaller reduction in insulin levels, and a smaller reduction in blood flow to the liver during exercise (19,20). 

Brown atrophy In malnutrition, the liver shows a decrease in cell and nucleus size, glycogen depletion, pigment deposits, occasional siderosis as well as proliferation of Kupffer cells. The liver as a whole becomes smaller (by as much as two thirds of its normal weight). Due to its pigment deposits, particularly siderin, the liver takes on a brown colour. These changes have been subsmned under the term brown atrophy (H. Popper, 194S). 

Fig. 31.8 Reye s syndrome (newborn) fine-droplet fatty changes of hepatocytes as well as glycogen depletion no signs of inflammation (PAS)...

Piehl, K. (1974). Time course for refilling of glycogen stores in human muscle fibres following exercise-induced glycogen depletion. Acta Physiol. Scand. 90,297-302. 

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