Effect of the acclimation to high environmental temperature on the activity of hepatic glycogen phosphorylase (a+b and a), liver glycogen content and blood glucose level in rats

2005 ◽  
Vol 30 (8) ◽  
pp. 563-568 ◽  
Author(s):  
Slavco Mitev ◽  
Suzana Dinevska-Kovkarovska ◽  
Biljana Miova
2019 ◽  
pp. 17-24
Author(s):  
Daphna Atar-Zwillenberg ◽  
Michael Atar ◽  
Gianni Morson ◽  
Udo Spornitz

The hormonal regulation of amphibian glycogen metabolism was studied in Xenopus laevis as a typical member of the anurans (tailless amphibians).The main focus of this study was given to the effects of various hormones on the glycogen/glucose balance in adult toads. We determined biochemically the liver and muscle glycogen contents as well as the blood glucose and lipid levels for a number of hormones and also diabetes inducing substances. Additionally, we examined ultrastructure changes in hepatocytes induced by the various treatments, and also investigated the activity of carbohydrate-relevant enzymes by histochemistry. With one exception, the liver glycogen content of Xenopus remained basically unchanged by the treatments or was even slightly enhanced. Only human chorionic gonadotropin, through which the vitellogenic response is triggered, prompts a significant decrease of liver glycogen in females. Under the same conditions the male liver glycogen content remained stable. Muscle glycogen contents were not affected by any of the treatments. Blood glucose and lipid levels on the other hand were elevated considerably in both sexes after application of either epinephrine or cortisol. The ultrastructural examination revealed a proliferation of Rough Endoplasmic Reticulum (RER) in hepatocytes from epinephrine treated toads of both sexes as well as from HCG treated females. By histochemistry, we detected an elevated glucose-6-phosphatase activity in the hepatocytes from toads treated with either epinephrine or cortisol. These treatments also led to enhanced glycogen phosphorylase activity in males, and to a slightly elevated glyceraldehyde-3-phosphate dehydrogenase activity in females. Our results show that the hepatic glycogen is extremely stable in adult Xenopus. Only vitellogenesis causes a marked utilization of glycogen. Since the blood glucose levels are elevated in epinephrine or cortisol treated toads without the liver glycogen being affected, we conclude that either protein and/or lipid metabolism are involved in carbohydrate metabolism in Xenopus laevis.


1982 ◽  
Vol 243 (3) ◽  
pp. R450-R453
Author(s):  
W. Langhans ◽  
N. Geary ◽  
E. Scharrer

The effects of feeding on liver glycogen content and blood glucose in the hepatic and hepatic portal veins were investigated in rats. Liver glycogen content decreased about 25% during meals both in rats refed after 12 h food deprivation (23 +/- 1 to 17 +/- 1 mg glycogen/g liver) and in ad libitum-fed rats taking fully spontaneous meals (44 +/- 2 to 32 +/- 2 mg/g). Liver glycogen began to increase within 30 min after meals in ad libitum-fed rats. Hepatic vein blood glucose levels at meal onset (118 +/- 4 mg/dl in the food-deprived rats, 127 +/- 4 in ad libitum-fed rats) and at meal end (155 +/- 3 and 166 +/- 5 mg/dl, respectively) were similar in the two groups. Portal vein blood glucose increased during meals in the previously food-deprived rats (83 +/- 4 to 116 +/- 6 mg/dl) but not in the ad libitum-fed rats (127 +/- 5 to 132 +/- 3 mg/dl). Mechanisms that may elicit prandial glycogenolysis and the possible role of this effect in the production of meal ending satiety are discussed.


2002 ◽  
Vol 93 (2) ◽  
pp. 798-804 ◽  
Author(s):  
Jean-Marc Lavoie ◽  
Yovan Fillion ◽  
Karine Couturier ◽  
Pierre Corriveau

The purpose of the present study was to test the hypothesis that the exercise-induced increase in insulin-like growth factor binding protein (IGFBP)-1 is not always linked to a decrease in blood glucose level and to examine whether the decreasing levels of liver glycogen during exercise may be associated with the increase in IGFBP-1. Three groups of rats were submitted to a 70-min treadmill exercise. One group of rats was fed normally, and the two other groups had their food intake restricted by 50% (50% fast) the night before the experiment. One of these two 50% fasted groups of rats was infused (intravenously) with glucose throughout exercise to maintain euglycemia. Exercise in noninfused 50% fasted rats, compared with the normally fed rats, resulted in significantly lower blood glucose ( minute 70) and insulin levels, significantly lower liver glycogen content, no change in IGF-I, and significantly higher increases in free fatty acid, glycerol, β-hydroxybutyrate, and IGFBP-1. Maintenance of euglycemia during exercise in glucose-infused 50% fasted rats reduced to a large extent the decrease in insulin levels but only slightly attenuated the lipid response and the IGFBP-1 response seen in noninfused 50% fasted rats. Comparisons of all individual liver glycogen and IGFBP-1 values revealed that liver glycogen values were highly ( P < 0.001) predictive of the IGFBP-1 response during exercise ( R = 0.564). The present results indicate that the IGFBP-1 response during exercise is not always linked to a decrease in plasma glucose and suggest that the increase in IGFBP-1 during exercise may be related to the decrease in liver glycogen content.


1970 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Zaied Ahmed Bhuyan ◽  
Begum Rokeya ◽  
Nuruzzaman Masum ◽  
Shahdat Hossain ◽  
Ishtiaq Mahmud

The present study evaluates the effects of powder and ethanol extract of Syzygium cumini seeds (1.25/ kg bw) treatment for 21 days on glucose homeostasis, serum insulin, serum lipids and liver glycogen content in streptozotocin (STZ) induced type 2 diabetic rats. The administration of S. cumini seed powder and ethanol extract for 21 days to type 2 diabetic rats significantly reduced the fasting glucose level although it did not alter the blood glucose level after glucose challenge. The insulin level and liver glycogen content also were not changed after dietary administration of Syzygium cumin powder or ethanol extract. In addition to hypoglycemic effect, the Syzygium cumini significantly ameliorated the lipid profile. The plasma LDL?cholesterol level, an atherogenic lipid, significantly (p < 0.01) decreased with a concurrent increase (p < 0.01) in the plasma HDL?cholesterol level, thus suggesting dietary Syzygium cumini could be used as one of the alternatives in the treatment of diabetes.    Key words: Syzygium cumini; Diabetes; Cholesterol DOI: http://dx.doi.org/10.3329/dujbs.v19i2.8959 DUJBS 2010; 19(2): 157-164


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