Inverse Relationship of Skeletal Muscle Glycogen from Wild-Type and Genetically Modified Mice to Their Phosphorylase a Activity

2002 ◽  
Vol 290 (2) ◽  
pp. 874-877 ◽  
Author(s):  
Louis H. Schliselfeld ◽  
Moris J. Danon
2008 ◽  
Vol 294 (1) ◽  
pp. E28-E35 ◽  
Author(s):  
Michale Bouskila ◽  
Michael F. Hirshman ◽  
Jørgen Jensen ◽  
Laurie J. Goodyear ◽  
Kei Sakamoto

Insulin promotes dephosphorylation and activation of glycogen synthase (GS) by inactivating glycogen synthase kinase (GSK) 3 through phosphorylation. Insulin also promotes glucose uptake and glucose 6-phosphate (G-6- P) production, which allosterically activates GS. The relative importance of these two regulatory mechanisms in the activation of GS in vivo is unknown. The aim of this study was to investigate if dephosphorylation of GS mediated via GSK3 is required for normal glycogen synthesis in skeletal muscle with insulin. We employed GSK3 knockin mice in which wild-type GSK3α and -β genes are replaced with mutant forms (GSK3α/βS21A/S21A/S9A/S9A), which are nonresponsive to insulin. Although insulin failed to promote dephosphorylation and activation of GS in GSK3α/βS21A/S21A/S9A/S9Amice, glycogen content in different muscles from these mice was similar compared with wild-type mice. Basal and epinephrine-stimulated activity of muscle glycogen phosphorylase was comparable between wild-type and GSK3 knockin mice. Incubation of isolated soleus muscle in Krebs buffer containing 5.5 mM glucose in the presence or absence of insulin revealed that the levels of G-6- P, the rate of [14C]glucose incorporation into glycogen, and an increase in total glycogen content were similar between wild-type and GSK3 knockin mice. Injection of glucose containing 2-deoxy-[3H]glucose and [14C]glucose also resulted in similar rates of muscle glucose uptake and glycogen synthesis in vivo between wild-type and GSK3 knockin mice. These results suggest that insulin-mediated inhibition of GSK3 is not a rate-limiting step in muscle glycogen synthesis in mice. This suggests that allosteric regulation of GS by G-6- P may play a key role in insulin-stimulated muscle glycogen synthesis in vivo.


2019 ◽  
Vol 20 (2) ◽  
pp. 78
Author(s):  
Nasrul Fathoni ◽  
M Anwar Djaelani ◽  
Sri Isdadiyanto

Kombucha tea beverage obtained by fermenting sweetened green tea for 12 days with Acetobacter xylinum and Saccharomyces which produce various kinds of organic acids, vitamins, and acts as a probiotic. The role of kombucha tea as a growth promoter is to that improve the metabolic process in the digestion of broiler chickens, so that nutrients can and fulfilled optimally for growth and development. The aim of this research was to analyze the sceletal muscle glycogen glycogen (Gallus gallus) after treat with kombucha tea in drinking water. Kombucha tea used is the result of fermentation of green tea for 12 days. This research used DOC chickens (Day Old Chicken) as much as 20 randomly divided into 4 treatments with concentration ie 0%, 10%, 20%, and 40% kombucha tea in drinking water for 32 days. The variables measured were skeletal muscle glycogen levels, body weight, feed consumption and drink consumption. The data obtained were analyzed using ANOVA followed by Duncan Test with 95% confidence level using SPSS 17.0 software. The results of this study showed that kombucha tea on skeletal muscle glycogen and feed consumption showed no significant difference, while on body weight and drink consumption showed significantly different results. Based on the results of the study, it can be concluded that giving kombucha tea in drinking water to a concentration of 40% has not been able to affect the skeletal muscle glycogen in broiler chickens. Key words: Kombucha tea, broiler chicken, glycogen skeletal muscle


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