Here we show that exogenous peroxynitrite results in nitration of phosphorylase as well inhibition glycogenolysis isolated intact mouse skeletal muscle during short-term repeated contractions. However, contractions the absence do not result or affect glycogenolysis, nor does addition antioxidants alter Thus is subject to redox control

Escherichia coli endotoxin (lipopolysaccharide) was shown to increase glycogenolysis in the perfused liver 2-3-fold. In isolated parenchymal liver cells, however, endotoxin did not influence glycogenolysis, whereas stimulation by endotoxin of glycogenolysis in the perfused liver could be blocked by aspirin. This suggests that the effect of endotoxin on liver glycogenolysis is mediated by eicosa...

Prostaglandins (PGs) are known to have effects on hepatic glucose metabolism. Some actions of PGs in intact liver systems may not involve PG effects directly at the level of the hepatocyte. To define the ability of structurally distinct prostaglandins to affect hepatocyte metabolism directly, the regulation of glycogenolysis was studied in hepatocytes isolated from male Sprague-Dawley rats. PGF...

Hepatocytes isolated from the liver of the common goldfish Carassius auratus L. with crude bacterial collagenase maintained ATP levels for at least 2 h. Glycogenolysis was maximally activated by 1 X 10(-6) M epinephrine and 5.8 X 10(-9) M glucagon. In liver cells incubated in calcium-free buffer containing 1 mM ethylene glycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid, basal glycogenolys...

The tumour-promoting phorbol ester, phorbol 12-myristate 13-acetate (PMA), when added to the perfused liver, stimulates glycogenolysis 2-fold. This stimulation is not seen when aspirin is present in the perfusion medium. In isolated parenchymal liver cells. PMA is not able to stimulate glycogenolysis, suggesting that its effect on glycogenolysis might be indirect and depends on the presence of ...

To determine whether the hepatic insulin resistance of obesity and type 2 diabetes is due to impaired insulin-induced suppression of glycogenolysis as well as gluconeogenesis, 10 lean nondiabetic, 10 obese nondiabetic, and 11 obese type 2 diabetic subjects were studied after an overnight fast and during a hyperinsulinemic-euglycemic clamp. Gluconeogenesis and glycogenolysis were measured using ...

13C NMR spectroscopy was used to assess flux rates of hepatic glycogen synthase and phosphorylase in overnight-fasted subjects under one of four hypoglucagonemic conditions: protocol I, hyperglycemic (approximately 10 mM) -hypoinsulinemia (approximately 40 pM); protocol II, euglycemic (approximately 5 mM) -hyperinsulinemia (approximately 400 pM); protocol III, hyperglycemic (approximately 10 mM...

Conversion of phosphorylase b to a has been considered to be a major mechanism for increasing phosphorylase activity and glycogenolysis. Certain observations have suggested that other factors are also involved (1, 2). In particular, anoxia produced faster glycogenolysis but less conversion of phosphorylase b to a than did glucagon in the perfused rat heart (1). Faster glycogenolysis in the anox...

The racemic prodrug BAY R3401 suppresses hepatic glycogenolysis. BAY W1807, the active metabolite of BAY R3401, inhibits muscle glycogen phosphorylase a and b. We investigated whether BAY R3401 reduces hepatic glycogenolysis by allosteric inhibition or by phosphatase-catalyzed inactivation of phosphorylase. In gel-filtered liver extracts, racemic BAY U6751 (containing active BAY W1807) was test...

It was shown in previous work that intravenous injection of serotonin caused a marked depletion of glycogen in rat hepatic tissues. Now that glycogenolysis brought about by epinephrine or glucagon is understood as a result of an activation of phosphorylase, the serotonin-induced glycogen breakdown may be mediated through the activation of the enzyme of glycogenolysis, because in liver fluke Fas...