scholarly journals RELATIONSHIP BETWEEN GLYCOGEN AND AGRANULAR ENDOPLASMIC RETICULUM IN RAT HEPATIC CELLS

1966 ◽  
Vol 14 (2) ◽  
pp. 135-146 ◽  
Author(s):  
J. C. H. DE MAN ◽  
A. P. R. BLOK ◽  
W. BEENS
Keyword(s):  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Female Rats ◽  
Glycogen Depletion ◽  
Hepatic Cells ◽  
High Resolution Autoradiography ◽  
Probable Role ◽  
Early Restoration ◽  
Adrenalectomized Rats

The relation between agranular reticulum and glycogen was studied in hepatic cells of female rats. Prolonged fasting of nonadrenalectomized rats did hot result ins complete liver glycogen depletion, whereas in adrenalectomized rats this could be accomplished within a few hours of fasting. In nonadrenalectomized rats a marked development of agranular reticulum associated with glycogen was found, whereas in adrenalectomized rats no such marked development of agranular reticulum was seen during glycogen depletion. Early glycogen restoration in glycogen-depleted liver cells of adrenalectomized rats was brought about 2-4 hr after the injection of 1 dose of cortisone or ½-1 hr after the injection of glucose. Early restoration of glycogen was accompanied and even preceded by a marked development of tubular agranular reticulum. A probable role of this organelle in glycogen synthesis and breakdown is discussed. High resolution autoradiography of tritium-labeled glucose incorporation offered some further illustration on the process of glycogen formation.

A study of kidney lysosomal acid phosphatase during compensatory renal hyperplasia in rats

1968 ◽  
Vol 46 (3) ◽  
pp. 499-502 ◽  
Author(s):  
B. M. Hegdekar
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzymes ◽  
Soluble Fraction ◽  
Female Rats ◽  
Enzyme Release ◽  
Lysosomal Fraction ◽  
Probable Role ◽  
Long Evans ◽  
Free Activity

Female rats of the Long-Evans hooded strain, 4–6 months old and weighing 275–300 grams, were subjected to unilateral nephrectomy and the acid phosphatase activity in the remaining kidney was studied at the end of 24, 48, 72 hours, and 8 days respectively. Most of the acid phosphatase was found in the particulate fraction in normal kidneys. The enzyme activity in the soluble fraction was found to have increased the second day after the operation, but decreased to the original level by the end of 72 hours. The free activity of the lysosomal fraction also increased by the end of second postoperative day. A change in the permeability of the lysosomal membrane before the enzyme release was observed. The probable role of lysosomal enzymes in the initiation of mitotic divisions during compensatory renal hyperplasia is discussed.

Tissue Glycogen Synthesis in Adrenalectomized Rats Fed Glycine-Containing Diets and Given Hydrocortisone

1958 ◽  
Vol 195 (3) ◽  
pp. 643-644 ◽  
Author(s):  
W. R. Todd ◽  
Marilouise Allen
Keyword(s):  
Body Weight ◽  
Muscle Glycogen ◽  
Control Diet ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Adrenal Hormone ◽  
Adrenalectomized Rats

Adrenalectomized rats were fed diets with or without added glycine for 36 hours; 4 hours later they were made to swim in 14°C water (the stress). Liver and muscle glycogen determinations at this time showed the levels to be essentially the same in the two groups of rats. When 1 mg of hydrocortisone per 100 gm body weight was given twice a day for 2 days prior to the stress, the glycine-fed animals showed nearly twice as much liver glycogen as the animals prefed the control diet. Muscle glycogen concentrations were not different. Adrenal hormone, glycine and stress are required to demonstrate the ‘protein effect’ of glycine. It now appears, however, that increased adrenal hormone is not a prerequisite.

scholarly journals NMR of glycogen in exercise

1999 ◽  
Vol 58 (4) ◽  
pp. 851-859 ◽  
Author(s):  
Thomas B. Price ◽  
Douglas L. Rothman ◽  
Robert G. Shulman
Keyword(s):  
Time Resolution ◽  
Muscle Glycogen ◽  
Time Course ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Invasive Technique ◽  
Human Populations ◽  
Glycogen Depletion ◽  
Non Invasive ◽  
C Nmr

Natural-abundance 13CNMR spectroscopy is a non-invasive technique that enables in vivo assessments of muscle and/or liver glycogen concentrations. Over the last several years, 13C NMR has been developed and used to obtain information about human glycogen metabolism with diet and exercise. Since NMR is non-invasive, more data points are available over a specified time course, dramatically improving the time resolution. This improved time resolution has enabled the documentation of subtleties of muscle glycogen re-synthesis following severe glycogen depletion that were not previously observed. Muscle and liver glycogen concentrations have been tracked in several different human populations under conditions that include: (1) muscle glycogen recovery from intense localized exercise with normal insulin and with insulin suppressed; (2) muscle glycogen recovery in an insulin-resistant population; (3) muscle glycogen depletion during prolonged low-intensity exercise; (4) effect of a mixed meal on postprandial muscle and liver glycogen synthesis. The present review focuses on basic 13C NMR and gives results from selected studies.

Hypothalamic hyperinsulinemia and obesity: role of adrenal glucocorticoids

1983 ◽  
Vol 245 (2) ◽  
pp. E194-E199
Author(s):  
B. M. King ◽  
A. R. Banta ◽  
G. N. Tharel ◽  
B. K. Bruce ◽  
L. A. Frohman
Keyword(s):  
Insulin Secretion ◽  
Food Intake ◽  
Plasma Insulin ◽  
Female Rats ◽  
Hypothalamic Obesity ◽  
Previous Conclusion ◽  
Glucose Levels ◽  
Corticosterone Treatment ◽  
Adrenalectomized Rats

The effects of adrenalectomy on the obesity and hyperinsulinemia induced by ventromedial hypothalamic (VMH) lesions were studied in female rats. Plasma insulin and glucose levels were assayed after a 4-h fast and 17 min after the initiation of a meal (6 ml sweetened milk in 7 min). The development of hypothalamic obesity was prevented by prior adrenalectomy and restored by administration of corticosterone. Adrenalectomy abolished both the basal and postabsorptive hyperinsulinemia observed in sham-adrenalectomized rats with VMH lesions. Corticosterone treatment of adrenalectomized animals enhanced both basal and postabsorptive insulin levels, but adrenalectomized rats with VMH lesions were hyperinsulinemic compared with animals with sham lesions only under the postabsorptive condition. Postabsorptive glucose levels were unaffected by either the lesion or adrenal ablation. The results support our previous conclusion that postabsorptive hyperinsulinemia is of greater importance than is basal hyperinsulinemia in the pathogenesis of hypothalamic obesity. Although the results are consistent with a stimulatory role of corticosterone on food intake mediating the postabsorptive hyperinsulinemia, a primary effect on CNS loci involved with the regulation of insulin secretion is also possible.

Postexercise muscle and liver glycogen metabolism in male and female rats

1987 ◽  
Vol 62 (3) ◽  
pp. 1250-1254 ◽  
Author(s):  
P. A. Ivey ◽  
G. A. Gaesser
Keyword(s):  
Sex Difference ◽  
Muscle Glycogen ◽  
Exercise Bout ◽  
Glycogen Metabolism ◽  
Liver Glycogen ◽  
Female Rats ◽  
Glycogen Depletion ◽  
Male And Female ◽  
Glycogen Repletion ◽  
Fast Twitch

Male and female Wistar rats were run for 5 min at 1.7 mph at a 17% grade to determine whether a sex difference exists in the rate of glycogen resynthesis during recovery in fast-twitch red muscle, fast-twitch white muscle, and liver. Rats were killed at one of three time points: immediately after the exercise bout, and at 1 or 4 h later. Males had significantly higher resting muscle glycogen levels (P less than 0.05). Exercise resulted in significant glycogen depletion in both sexes (P less than 0.01). Males utilized approximately 50% more glycogen during the exercise bout than females (P less than 0.05). During the food-restricted 4-h recovery period, muscle glycogen was repleted significantly during the 1st h (P less than 0.05). Liver glycogen was not depleted as a result of the exercise bout, but fell during the first h of recovery (P less than 0.05) and remained low during the subsequent 3 h. The greater glycogen utilization in red and white fast-twitch muscle during exercise by males could represent a true sex difference but could also be attributable in part to the males having performed more work as a result of 20% greater body mass. We conclude that no sex difference was observed in the rates of muscle glycogen repletion after exercise or in liver glycogen metabolism during and after exercise, and rapid postexercise muscle glycogen repletion occurred at a time of accelerated liver glycogen depletion.

Preferential resynthesis of muscle glycogen in fasting rats after exhausting exercise

1980 ◽  
Vol 238 (5) ◽  
pp. R328-R332 ◽  
Author(s):  
R. D. Fell ◽  
J. A. McLane ◽  
W. W. Winder ◽  
J. O. Holloszy
Keyword(s):  
Muscle Glycogen ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Glycogen Depletion ◽  
Glycogen Accumulation ◽  
Exhausting Exercise ◽  
Hindlimb Muscles ◽  
Carbohydrate Starvation ◽  
Fat Feeding ◽  
Very High

Despite carbohydrate starvation (fasting or fat feeding) considerable glycogen accumulation, ranging from 20 to 30 mumol glucose/g, occurred in hindlimb muscles of rats following exhausting exercise that caused severe muscle and liver glycogen depletion and hypoglycemia. The largest increase in muscle glycogen occurred during the first 3 h after exercise when plasma levels of glucagon and epinephrine were very high and insulin concentration was low. The concentrations of glycogen attained in different hindlimb muscles in the fasting and fat-fed animals were between 50 and 100% of the values found in rats fed carbohydrate after the exhausting exercise. In rats fed carbohydrate following exercise, liver glycogen accumulation greatly exceeds muscle glycogen accumulation. A remarkable difference in the response of liver glycogen was seen in the carbohydrate starved rats. In contrast to the rapid increase in muscle glycogen, liver glycogen was still essentially completely depleted in the fasting and fat-fed rats 24 h after exercise. This indicates that the glucose made available via gluconeogenesis was preferentialy channeled away from liver glycogen synthesis into muscle glycogen.

Glycogen Synthesis in Rat Liver from a Pool of Free Glucose

1993 ◽  
Vol 48 (1-2) ◽  
pp. 85-91 ◽  
Author(s):  
H. Schimassek ◽  
Ingrid Meißner
Keyword(s):  
Glycogen Synthesis ◽  
Specific Radioactivity ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Enzyme Complex ◽  
Indirect Pathway ◽  
Free Glucose ◽  
Complex Subject

Glycogen synthesis in isolated perfused livers or livers of anesthetized rats (in situ), was studied using radioactively labelled fructose, lactate, and inositol as substrates. The specific radioactivity of glucose and glycogen was measured at various times and compared with that of some intermediates. The results suggest that liver glycogen is formed from the pool of free glucose which in turn is fed by the so-called “direct and indirect pathway” of glycogen synthesis. This points to an important role of glucose-6-phosphatase, an enzyme complex subject to regulation by glucocorticoids, well known promoters of hepatic glycogen synthesis.

Distribution of newly formed hepatic glycogen in adrenalectomized rats as observed by radioautography after injection of 3H-galactose

1984 ◽  
Vol 42 ◽  
pp. 228-229
Author(s):  
J. E. Michaels ◽  
J. T. Hung ◽  
E. L. Cardell ◽  
R. R. Cardell
Keyword(s):  
Glycogen Synthesis ◽  
Hepatic Glycogen ◽  
Electron Microscopic ◽  
Routine Procedures ◽  
Silver Grains ◽  
Synthetic Glucocorticoid ◽  
Adrenalectomized Rats

In order to study early events of glycogen synthesis, we have used adrenalectomized (ADX) rats fasted overnight and injected with the synthetic glucocorticoid dexamethasone (DEX) to stimulate glycogen synthesis. Rats were given DEX 0-5 hr prior to sacrifice and injected with 2 mCi 3H-galactose 1 hr prior to sacrifice. Liver was prepared for light (LM) and electron microscopic (EM) radioautography by routine procedures.The concentration of silver grains over hepatic cytoplasm was measured in LM radioautographs using a Zeiss Videoplan. The hepatocytes were categorized as unlabeled if no silver grains (gr) were present, lightly labeled (<10gr/100 μm2 cytoplasm) or intensely labeled (>10 gr/1002 μm cytoplasm). Although very few hepatocytes showed heavy labeling after 1 hr treatment with DEX, by 2 hr after DEX treatment 8% of the cells distributed throughout the lobule were intensely labeled.

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