Possible role of cyclic amp in regulation of muscle tissue acid hydrolase activity in avitaminosis E and denervation

1976 ◽  
Vol 82 (3) ◽  
pp. 1335-1336
Author(s):  
A. V. Kozlov ◽  
B. F. Korovkin
1980 ◽  
Vol 28 (1) ◽  
pp. 82-86 ◽  
Author(s):  
A R Hand

GERL exhibits a number of structural properties, such as its location at the trans face of the Golgi apparatus, thick limiting membranes with occasional coated regions, and close relationship to the ER, which are similar in all cells wehre it has been identified. Acid hydrolase activity and the formation of lysosomes, also considered characteristic of GERL, have been shown to be less consistent properties of GERL in some cells. Finally, GERL and the Golgi saccules of certain cells undergo significant changes in their cytochemical and structural properties in response to specific alterations in cellular activity. These variations are important for at least two reasons: first, they indicate the care required in differentiating GERL from the Golgi saccules based on limited cytochemical observations; second, and most important, they may yield information regarding the biogenetic and functional relationships between the ER, Golgi saccules, and GERL, such as the origin of GERL in various cells and the role of each organelle in the processing of lysosomal and secretory proteins.


1993 ◽  
Vol 4 (6) ◽  
pp. 204-209 ◽  
Author(s):  
Wolfgang Schmid ◽  
Doris Nitsch ◽  
Michael Boshart ◽  
Günther Schütz

1992 ◽  
Vol 283 (1) ◽  
pp. 261-264 ◽  
Author(s):  
N Casals ◽  
N Roca ◽  
M Guerrero ◽  
G Gil-Gómez ◽  
J Ayté ◽  
...  

We have explored the role of mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase in regulating ketogenesis. We had previously cloned the cDNA for mitochondrial HMG-CoA synthase and have now studied the regulation in vivo of the expression of this gene in rat liver. The amount of processed mitochondrial HMG-CoA synthase mRNA is rapidly changed in response to cyclic AMP, insulin, dexamethasone and refeeding, and is greatly increased by starvation, fat feeding and diabetes. We conclude that one point of ketogenic control is exercised at the level of genetic expression of mitochondrial HMG-CoA synthase.


1981 ◽  
Vol 200 (3) ◽  
pp. 509-514 ◽  
Author(s):  
B Bréant ◽  
S Keppens ◽  
H De Wulf

Vasopressin and alpha-adrenergic agonists are known to be potent cyclic AMP-independent Ca2+-dependent activators of liver glycogen phosphorylase. When hepatocytes are pre-incubated with increasing concentrations of vasopressin or of the alpha-agonist phenylephrine, they become progressively unresponsive to a second addition of the respective agonist. The relative abilities of six vasopressin analogues and of five alpha-agonists to activate glycogen phosphorylase and to cause subsequent desensitization are highly correlated, indicating that the same vasopressin and alpha-adrenergic receptors are involved in both responses. About 5-times-higher peptide concentrations are needed to desensitize the cells than to activate their glycogen phosphorylase, whereas the concentrations of alpha-agonists required for the desensitization are only twice those needed for the activation of phosphorylase. The desensitization is not mediated by a perturbation in the agonist-receptor interaction. It is clearly heterologous, i.e. it is not agonist-specific, and must therefore involve a mechanism common to both series of agonists. The evidence for a role of Ca2+ movements or phosphatidylinositol turnover is briefly discussed.


1979 ◽  
Vol 27 (1) ◽  
pp. 57-61 ◽  
Author(s):  
D.L. Kaminski ◽  
M.J. Ruwart ◽  
Y.G. Deshpande
Keyword(s):  

1978 ◽  
Vol 234 (6) ◽  
pp. E606
Author(s):  
J G Spenney

Acetylsalicylic acid hydrolase activity of rabbit fundic gastric mucosa has been isolated from the soluble 100,000 X g supernate. The enzymatic activity was partially purified by ammonium sulfate precipitation. The Km for acetylsalicylate was 2 mM and pH optimum was 8.6. The activity was insensitive to ionic strength, slightly inhibited by inclusion of 100 mM Cl-, and demonstrated no requirement for Ca2+ or Mg2+. Acetylsalicylic acid esterase was markedly inhibited by sodium cholate and sodium dodecyl sulfate. The enzyme was insensitive to sulfhydryl reagents with the exception of p-chloromercuribenzenesulfonic acid, which markedly inhibited the enzyme. Diisopropyl fluorophosphate (DFP) inhibited enzymatic activity with a Ki of 9 X 10(-9)M. Eserine was also inhibitory with a Ki of 0.25 mM. Inhibition by DFP at low concentration and by eserine at millimolar concentrations suggests that this enzyme is related to the group of aliphatic esterases. Identification of potent inhibitors will enable studies to define the role of this enzyme with the use of experimental preparations in which systemic toxicity can be avoided.


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