Changes in skeletal muscle glycogenolysis after prolonged cold exposure and repeated injections with isoproterenol

1979 ◽  
Vol 57 (9) ◽  
pp. 938-943 ◽  
Author(s):  
M. C. Thibault ◽  
C. Côté ◽  
J. Vallières
Keyword(s):  
Adenylate Cyclase ◽  
Cold Stress ◽  
Tibialis Anterior ◽  
Skeletal Muscles ◽  
Glycogen Phosphorylase ◽  
Phosphorylase Kinase ◽  
Adenylate Cyclase System ◽  
Great Capacity ◽  
Contracting Muscle

Wistar rats were either given daily injections of isoproterenol (ISO) (15 μg/100 g per day) or exposed to 6 °C for 4 or 12 weeks (cold acclimated (CA)). After a 4-week exposure to cold and to ISO, acute cold stress (4 h at –18 °C) produced a 48% depletion of glycogen in the tibialis anterior of control rats while it did not significantly affect the levels in ISO-treated and CA animals. ISO treatment enhanced the in vivo response of phosphorylase kinase and glycogen phosphorylase to epinephrine (EPI) in the tibialis anterior, a fast contracting muscle. In the soleus, a slow contracting muscle known to be more sensitive to catecholamines, chronic treatment with ISO also resulted in increased basal and EPI-stimulated adenylate cyclase activity. No evidence could be found for an alteration of the glycogenolytic pathway (adenylate cyclase system, phosphorylase kinase, and glycogen phosphorylase) in fast contracting skeletal muscles of CA rats. It is concluded that ISO-treated and CA rats, which have a great capacity for nonshivering thermogenesis, do not rely on their muscle carbohydrate reserves during cold stress. It might be suggested that plasma levels of catecholamines higher than those produced by exposure to 6 °C are required to alter glycogenolytic mechanisms in fast contracting rat skeletal muscles.

Desensitization of the ?-adrenoceptor-adenylate cyclase system of immature erythrocytes by in-vivo treatment of rats with isoprenaline

1981 ◽  
Vol 317 (4) ◽  
pp. 294-301 ◽  
Author(s):  
G. Wiemer ◽  
G. Kaiser ◽  
J. Dietz ◽  
M. Reinhardt ◽  
A. Wellstein ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Adenylate Cyclase System ◽  
In Vivo Treatment

Control of adipose tissue lipolysis in ectotherm vertebrates

1992 ◽  
Vol 263 (4) ◽  
pp. R857-R862 ◽  
Author(s):  
R. H. Migliorini ◽  
J. S. Lima-Verde ◽  
C. R. Machado ◽  
G. M. Cardona ◽  
M. A. Garofalo ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Adenylate Cyclase ◽  
Lipolytic Activity ◽  
Adenylate Cyclase System ◽  
Triacylglycerol Lipase ◽  
Membrane Bound ◽  
Adipose Tissue Lipolysis ◽  
Toad Bufo

Lipolytic activity of fish (Hoplias malabaricus), toad (Bufo paracnemis), and snake (Philodryas patagoniensis) adipose tissue was investigated in vivo and in vitro. Catecholamines or glucagon did not affect the release of free fatty acids (FFA) by incubated fish and toad adipose tissue. Catecholamines also failed to activate snake adipose tissue lipolysis, which even decreased in the presence of epinephrine. However, glucagon stimulated both the lipolytic activity of reptilian tissue in vitro and the mobilization of FFA to plasma when administered to snakes in vivo. The release of FFA from incubated fish, amphibian, and reptilian adipose tissue increased markedly in the presence of cAMP or xanthine derivatives, inhibitors of phosphodiesterase. Forskolin or fluoride, activators of specific components of the adenylate cyclase system, strongly stimulated toad adipose tissue lipolysis. The data suggest that adipocyte triacylglycerol lipase of ectotherm vertebrates is activated by a cAMP-mediated phosphorylation and that the organization of the membrane-bound adenylate cyclase system is similar to that of mammals.

THE PROPERTIES OF ADENYLATE CYCLASE SYSTEM IN EMBRYONIC SKELETAL MUSCLES

1981 ◽  
Vol 9 (2) ◽  
pp. 208P-208P
Author(s):  
M. N. Pertseva ◽  
T. I. Mazina ◽  
L. A. Kuznetzova ◽  
S. A. Plesneva
Keyword(s):  
Adenylate Cyclase ◽  
Skeletal Muscles ◽  
Adenylate Cyclase System

scholarly journals Aging of Skeletal Muscle Does Not Affect the Response of Satellite Cells to Denervation

2003 ◽  
Vol 51 (7) ◽  
pp. 853-863 ◽  
Author(s):  
Eduard I. Dedkov ◽  
Andrei B. Borisov ◽  
Anton Wernig ◽  
Bruce M. Carlson
Keyword(s):  
Skeletal Muscle ◽  
Postnatal Development ◽  
Satellite Cells ◽  
Tibialis Anterior ◽  
Proliferative Activity ◽  
Skeletal Muscles ◽  
Advanced Age ◽  
Muscle Denervation ◽  
Old Rats

Satellite cells (SCs) are the main source of new fibers in regenerating skeletal muscles and the key contributor to extra nuclei in growing fibers during postnatal development. Aging results in depletion of the SC population and in the reduction of its proliferative activity. Although it has been previously determined that under conditions of massive fiber death in vivo the regenerative potential of SCs is not impaired in old muscle, no studies have yet tested whether advanced age is a factor that may restrain the response of SCs to muscle denervation. The present study is designed to answer this question, comparing the changes of SC numbers in tibialis anterior (TA) muscles from young (4 months) and old (24 months) WI/HicksCar rats after 2 months of denervation. Immunostaining with antibodies against M-cadherin and NCAM was used to detect and count the SCs. The results demonstrate that the percentages of both M-cadherin- and NCAM-positive SCs (SC/Fibers × 100) in control TA muscles from young rats (5.6 ± 0.5% and 1.4 ± 0.2%, respectively) are larger than those in old rats (2.3 ± 0.3% and 0.5 ± 0.1%, respectively). At the same time, in 2-month denervated TA muscles the percentages of M-cadherin and NCAM positive SC are increased and reach a level that is comparable between young (16.2 ± 0.9% and 7.5 ± 0.5%, respectively) and old (15.9 ± 0.7% and 10.1 ± 0.5%, respectively) rats. Based on these data, we suggest that aging does not repress the capacity of SC to become activated and grow in the response to muscle denervation.

Prolonged exposure to halothane and associated changes in carbohydrate metabolism in rat muscles in vivo

1998 ◽  
Vol 84 (4) ◽  
pp. 1470-1474 ◽  
Author(s):  
Luis D. M. C.-B. Ferreira ◽  
T. Norman Palmer ◽  
Paul A. Fournier
Keyword(s):  
Skeletal Muscles ◽  
Glycogen Phosphorylase ◽  
Prolonged Exposure ◽  
Glycogen Metabolism ◽  
Activity Ratios ◽  
Fructose 1,6 Bisphosphate ◽  
Glycogen Breakdown ◽  
Stimulation Of

Halothane, an anesthetic presently used in animal experimentation, is reported to stimulate glycogen breakdown in isolated preparations of rat skeletal muscles, suggesting that it may not be a suitable anesthetic for the study of glycogen metabolism in rats in vivo. The purpose of this study was to establish whether prolonged exposure to halothane in rats in vivo is associated with accelerated glycogenolysis. Exposure of rats to halothane for up to 1 h was not accompanied by either any change in the levels of glycogen or increase in activity ratios of glycogen phosphorylase in muscles, irrespective of their fiber compositions. In marked contrast, the levels of lactate, inorganic phosphate, glucose 1-phosphate, glucose 6-phosphate, fructose 1,6-bisphosphate, and fructose 2,6-bisphosphate changed progressively during anesthesia. Accordingly, the interpretation of muscle metabolite levels must be performed with caution in experiments involving prolonged exposure to halothane. Overall, our findings indicate that the reported halothane-mediated stimulation of glycogen breakdown in vitro is likely to be an artifact and that halothane is a suitable anesthetic for experiments concerned with glycogen metabolism in rats.

scholarly journals Stabilization and solubilization of bovine corpus-luteum adenylate cyclase. The effects of guanosine triphosphate, guanosine 5′-[β,γ-imido]triphosphate, sodium fluoride and Tris/hydrochloric acid concentration on enzyme activity

1978 ◽  
Vol 169 (1) ◽  
pp. 133-142 ◽  
Author(s):  
John L. Young ◽  
David A. Stansfield
Keyword(s):  
Adenylate Cyclase ◽  
Corpus Luteum ◽  
Active State ◽  
Adenylate Cyclase System ◽  
Hydrochloric Acid Concentration ◽  
Bovine Corpus Luteum ◽  
Ionic Detergent ◽  
Stimulation Of

1. Adenylate cyclase of the washed 600g sediment of bovine corpus-luteum homogenate is stimulated by p[NH]ppG (guanosine 5′-[β,γ-imido]triphosphate), the imido analogue of GTP, and to a lesser extent by GTP itself. Activation by p[NH]ppG is not reversed by extensive washing before assay, but can, however, be reversed by NaF. 2. Both p[NH]ppG and NaF stabilize the enzyme during incubation at 37°C. NaF also causes an irreversible activation, but only of part of the potentially NaF-activatable adenylate cyclase; there are possibly two components of the adenylate cyclase system, which can be distinguished by their response to NaF. 3. Solubilization of the adenylate cyclase activity in the 600g sediment, by using the non-ionic detergent Lubrol-PX, gave variable yields. A relationship between the magnitude of NaF stimulation of the 600g-sediment enzyme and the yield of soluble activity derived from the sediment was recognized. The results suggest that the pre-existing state of the enzyme complex in vivo is reflected by the response in vitro to NaF and may determine the success with which activity can be solubilized. 4. The absolute yields of soluble activity could be increased by p[NH]ppG preactivation of the 600g sediment. During the development of the maximally active state by preincubation with p[NH]ppG the enzyme passes through a stage in which Lubrol solubilization is increased, but the maximally active state is itself less amenable to solubilization. p[NH]ppG activation causes the appearance of NaF-inhibited states, which appear to be preferentially solubilized by Lubrol-PX.

scholarly journals Activation of hepatic glycogen phosphorylase b in vivo by sodium sulphate in normal (Wistar) and phosphorylase b kinase-deficient (gsd/gsd) rats

1986 ◽  
Vol 239 (2) ◽  
pp. 493-496 ◽  
Author(s):  
G Lutaya ◽  
L M Rodrigues ◽  
J R Griffiths
Keyword(s):  
Glycogen Phosphorylase ◽  
Tight Binding ◽  
Sodium Sulphate ◽  
Hepatic Glycogen ◽  
Phosphorylase Kinase ◽  
Rat Strains ◽  
Intravenous Injections ◽  
Glycogen Phosphorylase B

Sulphate ions have been known for some years to enhance the activity of hepatic glycogen phosphorylase b in vitro. Here we report that intravenous injections of 4.92 mmol of Na2SO4/kg body wt. to rats induced marked hepatic glycogenolysis in vivo, accompanied by polyuria, glycosuria and a mild hyperglycaemia. These effects were observed both in normal (Wistar) rats and in gsd/gsd rats that lacked hepatic phosphorylase kinase. In both rat strains the activity of glycogen phosphorylase in liver extracts was enhanced by pretreatment of the animals with Na2SO4, but in phosphorylase kinase-deficient livers the enhancement was solely in phosphorylase b activity, whereas both the a and b forms of the enzyme were activated in normal livers. Hepatic glycogenolysis was also induced by perfusing rat livers, both normal and gsd/gsd, with 25 mM-Na2SO4. Under these conditions both the rat strains showed only enhanced activities of glycogen phosphorylase b. This suggested that the increased activity of phosphorylase a in the extracts of normal livers after Na2SO4 administration in vivo was due to a hormonally mediated conversion of the b form into the a form. The activation of glycogen phosphorylase b was stable to dilution and appeared to be due to a long-lasting structural change in the enzyme or very tight binding of an activator.

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