In recent years the classification of glycogen storage disease has been based on the demonstration of a specific enzyme defect for each type (14). Type I, glycogenosis or von Gierke's disease, results from the lack of glucose 6-phosphatase (1). Type II, or Pompe's disease, is characterized clinically by the severity of the disease with cardiovascular complications causing death usually before t...

1. Changes in the content and concentration of glycogen and in the activity of a number of enzymes involved in glucose and glycogen metabolism were studied in the rat hemidiaphragm after unilateral denervation. 2. After nerve section the tissue hypertrophies; this hypertrophy is said to be confined to the smaller red fibres and not to the white. 3. The total hexokinase activity increases, where...

Romalea guttata Houttuyn (= R. microptera Beavois) is flightless, lethargic, aposematic, and chemically defended. R. guttata stores large quantities of two adipokinetic hormone (AKH) family peptides in its corpora cardiaca. In adults, these peptides (Rom-CC-I and Grb-AKH) activate fat body glycogen phosphorylase but are not hypertrehalosemic. Because juvenile R. guttata contain sufficient pepti...

A study of the chemical and kinetic properties of a series of transplantable, chemically induced rat hepatomas has revealed profound alterations in isozyme patterns of glycogen synthetase and phosphorylase. Highly differentiated, slow-growing hepatomas retain the liver-type isozymes, but with decreased differentiation and increased growth rate these are largely or entirely replaced by nonhepati...

The activity of glycogen phosphorylase (1,4-alpha-D-glucan:orthophosphate alpha-D-glucosyltransferase, EC 2.4.1.1) is controlled by a cyclic phosphorylation-dephosphorylation process through the action of the interconverting enzymes, phosphorylase b kinase (ATP:phosphorylase-b phosphotransferase, EC 2.7.1.38) and phosphorylase a phosphatase (phosphorylase a phosphohydrolase, EC 3.1.3.17). In mu...

The ability to control the rates of metabolic processes in response to changes in the internal or external environment is an indispensable attribute of living cells that must have arisen with life’s origin. This adaptability is necessary for conserving the stability of the intracellular environment (homeostasis), which is, in turn, essential for maintaining an efficient functional state. In the...

A study of the chemical and kinetic properties of a series of transplantable, chemically induced rat hepatomas has revealed profound alterations in isozyme patterns of glycogen synthetase and phosphorylase. Highly differentiated, slow-growing hepatomas retain the liver-type isozymes, but with decreased differentiation and increased growth rate these are largely or entirely replaced by nonhepati...

Fasting of second-day fifth instar larval Manduca sexta leads to a rapid decrease in hemolymph glucose concentration from 3.39+/-0.29 to 0.33+/-0.06 mM in 1 h, along with a decrease in the fructose-2,6-bisphosphate content in the fat body (from 5.92+/-0.31 to 2.80+/-0.47 nmol fructose-2,6-bisphosphate/g fat body in 3 h) and activation of fat body glycogen phosphorylase (from 16% to 55-65% phosp...