Glycogen and starch are the major readily accessible energy storage compounds in nearly all living organisms. Glycogen is a very large branched glucose homopolymer containing about 90% alpha-1,4-glucosidic linkages and 10% alpha-1,6 linkages. Its synthesis and degradation constitute central pathways in the metabolism of living cells regulating a global carbon/energy buffer compartment. Glycogen...

Northern blot analysis showed that human muscle glycogen phosphorylase is developmentally regulated in human adult and fetal skeletal muscle. Furthermore, muscle phosphorylase mRNA expression is temporally regulated in the C2C12 mouse muscle cell line. To define regulatory elements that control expression of the human muscle glycogen phosphorylase gene, the structure of the 5' end of the gene w...

It has been reported that an enzyme-glycogen phosphorylase [EC 2.4.1.1] histochemical re‐ action is observed in differentiated hepatic or muscular tissues and in some proliferating tis‐ sues including fetus and carcinoma [1,2]. In the human stomach, a phosphorylase reaction appears in the undifferentiated gastric epithelium at the midpoint of fetal life, and is not de‐ tected in gastric epithel...

The molecular and cellular mechanisms behind glycogen metabolism and the energy metabolite translocation between mammal neurons and astrocytes have been well studied. A mechanism is proposed for rapid mobilization of local energy stores to support energydependent transepithelial ion transport in gills of the Mozambique tilapia (Oreochromis mossambicus). A novel gill glycogen phosphorylase isofo...

The glycogen phosphorylase of Dictyostelium discoideum has been purified over 200-fold from cells in the culmination stage of development. Analytical gel electrophoresis of the purified enzyme indicates one major protein band with a molecular weight of approximately 210,000. Gel elution verified the presence of phosphorylase activity associated with the protein band. Electrophoresis of partiall...

Cori and his colleagues (l-6) discovered and elucidated the series of reversible chemical reactions by which glucose is transformed into glycogen in animal tissues. These reactions are catalyzed by a group of enzymes, the most fundamental of which is phosphorylase, the enzyme which catalyzes the condensation of glucose-l-phosphate (Cori ester) to starch or glycogen. The properties of phosphoryl...

Postmortem myofiber histochemistry was studied in longissimus muscles of pigs with differing degrees of stress susceptibility (SS). The histochemical reactivity of phosphorylase and the stainability of glycogen by the periodic acid-Schiff (PAS) reaction was enhanced in samples taken approximately 20 min. postmortem. In later postmortem samples from SS animals killed by stress treatment, phospho...

Glycogenolysis was studied in glycogen-rich perfused livers in which glycogen phosphorylase was fully converted into the a form by exposure of the livers to dibutyryl cyclic AMP. We monitored intracellular Pi by 31P n.m.r. Perfusion with Pi-free medium during 30 min caused a progressive decrease of the Pi signal to 50% of its initial value. In contrast, exposure of the livers to KCN and/or 2,4-...

In the invertebrate liver fluke, Fasciola hepatica, there is evidence that 5-hydroxytryptamine (serotonin) increases glycolysis (1, 2), glycogenolysis (1), and phosphorylase activity (3). However, previous studies in mammalian liver, in vitro and in vivo, have yielded conflicting results concerning the effect of serotonin on hepatic glycogen content, hepatic phosphorylase, and blood glucose. So...