Sarcoplasmic vesicles and ~-glycogen particles 30-40 m# in diameter were isolated from perfused rabbit skeletal muscle by the differential precipitation-centrifugation method. This microsomal fraction was subjected to zonal centrifugation on buffered sucrose gradients, in a B X I V Anderson type rotor, for 15 hr at 45,000 rpm in order to separate the two cytoplasmic organelles. Zonal profiles o...

The aim of this study was to determine the role of the phosphorylation state of glycogen synthase and glycogen phosphorylase in the regulation of muscle glycogen repletion in fasted animals recovering from high-intensity exercise. Groups of rats were swum to exhaustion and allowed to recover for up to 120 min without access to food. Swimming to exhaustion caused substantial glycogen breakdown a...

We have determined uterine glycogen content, metabolizing enzyme expression and activity in the mink, a species that exhibits obligatory embryonic diapause, resulting in delayed implantation. Gross uterine glycogen concentrations were highest in estrus, decreased 50% by diapause and 90% in pregnancy (P ≤ 0.05). Endometrial glycogen deposits, which localized primarily to glandular and luminal ep...

Pompe disease, also known as glycogen storage disease (GSD) type II, is caused by deficiency of lysosomal acid α-glucosidase (GAA). The resulting glycogen accumulation causes a spectrum of disease severity ranging from a rapidly progressive course that is typically fatal by 1 to 2 years of age to a slower progressive course that causes significant morbidity and early mortality in children and a...

Much attention has been centered recently on the pathways of glycogen metabolism. The demonstration of the presence of a uridine diphosphoglucose-linked pathway for glycogen synthesis (1) and the extensive studies which followed (Z-6) have provided strong evidence for the existence in muscle of a metabolic cycle in which the uridine pathway is involved in the synthesis and phosphorylase catalyz...

Sarcoplasmic vesicles and ~-glycogen particles 30-40 m# in diameter were isolated from perfused rabbit skeletal muscle by the differential precipitation-centrifugation method. This microsomal fraction was subjected to zonal centrifugation on buffered sucrose gradients, in a B X I V Anderson type rotor, for 15 hr at 45,000 rpm in order to separate the two cytoplasmic organelles. Zonal profiles o...

Fasting or starvation of 1(st)- and 2(nd)-day fifth instar Manduca sexta larvae leads to rapid activation of fat body glycogen phosphorylase. Under feeding conditions, 21-29% of the phosphorylase was found in the active form. However, after only one hour of starvation, the active form increased to 55-65%. In larvae on the 3(rd)-day there was a slower increase in the activation, requiring three ...

The role of glucose 6-P (glucose 6-phosphate) in regulating the activation state of glycogen synthase and its translocation is well documented. In the present study, we investigated the effects of glucose 6-P on the activation state and compartmentation of phosphorylase in hepatocytes. Glucose 6-P levels were modulated in hepatocytes by glucokinase overexpression or inhibition with 5-thioglucos...

Rabbit skeletal muscle glycogen synthetase I has been purified and obtained essentially free of phosphor-y&e, phosphorylase khmse, and glycogen synthetase kinase. Using the purified glycogen synthetase as substrate, it was determined that two separable adenosine 3’,5’-monophosphate (cyclic AMP)-dependent protein kinase fractions from skeletal muscle each catalyze the conversion of glycogen synt...

mycelium from 24 h, reaching a maximum at 3-4 days then dcclining by day seven. Electron micrographs of the mycelium at later times was complicated by the state of the mycelium, but few granules could be seen. The granules, which were 100-400 A in diameter, appeared to be polysaccharide on the basis of periodic acid-thiocarbohydrazide-silver proteinate staining [ 21. Large amounts of lipid mate...