Glycogen Breakdown in Muscle Extract and Yeast Juice

The action of steroids on glycogen breakdown in surviving muscle.

1. Minced muscle and liver of normal rats produce glycogen from glucose-l-phosphate in vitro. 2. If, after a starvation period, the glycogen content falls below 200 mg./100 g., minced liver and muscle do not produce glycogen from glucose-lphosphate. However, if glycogen is added as well, additional glycogen is produced, just as with pure enzyme solutions. 3. In adrenalectomized, adynamic rats t...

The hydrolysis of glycogen by a glycerol extract of muscle.

BARBOUR [1929] found that when glycogen is hydrolysed by a glycerol extract of skeletal muscle or of liver, the reducing activity appearing, expressed as glucose, is only about 30% of the glycogen disappearing. Case [1931] and Gray [1935] were able to confirm this observation, but Carruthers [1935] did not obtain consistent results. From the products of hydrolysis Barbour isolated, by a relativ...

Epinephrine-stimulated glycogen breakdown activates glycogen synthase and increases insulin-stimulated glucose uptake in epitrochlearis muscles.

Epinephrine increases glycogen synthase (GS) phosphorylation and decreases GS activity but also stimulates glycogen breakdown, and low glycogen content normally activates GS. To test the hypothesis that glycogen content directly regulates GS phosphorylation, glycogen breakdown was stimulated in condition with decreased GS activation. Saline or epinephrine (0.02 mg/100 g rat) was injected subcut...

Some factors influencing the formation of Robison ester from glycogen and inorganic phosphate in muscle extract.

The Role of Skeletal Muscle Glycogen Breakdown for Regulation of Insulin Sensitivity by Exercise

Glycogen is the storage form of carbohydrates in mammals. In humans the majority of glycogen is stored in skeletal muscles (∼500 g) and the liver (∼100 g). Food is supplied in larger meals, but the blood glucose concentration has to be kept within narrow limits to survive and stay healthy. Therefore, the body has to cope with periods of excess carbohydrates and periods without supplementation. ...