Biosynthesis of Fatty Acids in Liver and Intestine of Intact Normal, Fasted and X-Irradiated Rats

1956 ◽  
Vol 185 (3) ◽  
pp. 577-582 ◽  
Author(s):  
John G. Coniglio ◽  
Donald B. McCormick ◽  
Granville W. Hudson
Keyword(s):  
Fatty Acids ◽  
Direct Relationship ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Fasting Period ◽  
Glycogen Concentration ◽  
X Irradiation ◽  
Total Body ◽  
Fasted Rats

A 72-hour fasting period affects intestinal incorporation of C14-acetate into fatty acids to a smaller extent that it does hepatic incorporation. Glycogen concentration and hepatic incorporation of acetate into fatty acids increases in irradiated, fasted rats (750 r total-body x-irradiation) compared to fasted controls. Intestinal incorporation of C14-acetate into fatty acids decreases in the irradiated rat. A direct relationship between the amount of liver glycogen present and the amount of incorporation of C14 into fatty acids was not observed at these levels of hepatic glycogen and lipogenesis.

Hepatic Glycogen, Lipogenesis and Glucose-6-Phosphatase in X-Irradiated and Control Rats

1957 ◽  
Vol 191 (2) ◽  
pp. 350-354 ◽  
Author(s):  
John G. Coniglio ◽  
John C. Kirschman ◽  
Granville W. Hudson
Keyword(s):  
Fatty Acids ◽  
Liver Glycogen ◽  
Total Activity ◽  
Hepatic Glycogen ◽  
Hepatic Lipogenesis ◽  
Hepatic Glucose ◽  
X Irradiation ◽  
Total Body ◽  
And Control ◽  
Fasted Rats

Incorporation of C14-acetate into hepatic fatty acids increased in irradiated, fasted rats (750 r total-body x-irradiation) compared to fasted controls as early as 6 hours postirradiation. At this time hepatic glycogen in irradiated animals was lower than in controls and lower than in irradiated animals at 30 minutes postirradiation. Incorporation remained constant at 12 hours postirradiation but glycogen concentration in irradiated rats was increased over controls. At 18 hours the irradiated rat exhibited both increased hepatic glycogen and increased lipogenesis. The increase in liver glycogen in irradiated, fasted rats could be prevented effectively by administration of S,ß aminoethylisothiouronium bromide 10 minutes prior to irradiation. In those irradiated rats in which symptoms of toxicity of the drug were not severe, enhancement of hepatic lipogenesis either was not prevented or was only partly prevented. The results are consistent with the hypothesis that liver glycogen is not the sole factor contributing to increased hepatic lipogenesis in irradiated fasted rats. Assay for hepatic glucose-6-phosphatase at 0.5, 24 and 48 hours after 750 or 1000 r total-body x-irradiation revealed no significant change due to the irradiation. However, both concentration and total activity of the enzyme were increased by fasting.

Effects of Epinephrine on Carbohydrate Metabolism in Underfed and ad Libitum-Fed Rats

1957 ◽  
Vol 190 (2) ◽  
pp. 239-242
Author(s):  
B. N. Spirtos ◽  
R. G. Stuelke ◽  
N. S. Halmi
Keyword(s):  
Carbohydrate Metabolism ◽  
Blood Sugar ◽  
Blood Lactate ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Commercial Diet ◽  
Ad Libitum ◽  
Sugar Levels ◽  
Fasted Rats

Rats fed 10 gm of a commercial diet for 4–5 weeks and fasted for 24 hours showed less rise in liver glycogen and blood sugar levels in response to the injection of epinephrine than did ad libitum-fed-fasted rats. Gastrocnemius glycogen levels were found to be higher in underfed-fasted animals and fell to the same extent as in ad libitum fed-fasted animals when epinephrine was given. Blood lactate concentrations, however, rose less markedly in the underfed-fasted group. This may have been at least partly responsible for the diminished rise in hepatic glycogen and blood sugar.

Some Effects of Prolonged Undernutrition on Carbohydrate Metabolism in Rats

1956 ◽  
Vol 187 (3) ◽  
pp. 432-436 ◽  
Author(s):  
N. S. Halmi ◽  
B. N. Spirtos
Keyword(s):  
Insulin Sensitivity ◽  
Blood Sugar ◽  
Initial Level ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Glycogen Concentration ◽  
Insulin Tolerance ◽  
Lower Blood ◽  
Ad Libitum ◽  
Sugar Levels

A) Rats fed 10 gm of ground Rockland diet/day for 4–6 weeks and then fasted for 24 hours showed an enhanced insulin sensitivity as compared with ad libitum-fed rats that were fasted for the same length of time. The fasting blood sugar and liver glycogen concentrations were significantly higher in underfed animals. B) Underfed rats were fasted 24 hours, then fed 5 gm/ 100 gm body weight and tested 8 hours later. These rats exhibited a) no greater insulin sensitivity, b) lower blood sugar levels and c) a smaller rise in liver glycogen concentration than similarly treated ad libitum-fed animals. Intestinal absorption of glucose was not diminished in the undernourished rats. C) Cortisone treatment (0.5 mg/100 gm body wt/day for 5 days) abolished the insulin sensitivity of underfed rats without altering the hepatic glycogen concentration. Somatotrophin (0.5 mg Armour standard equivalent/100 gm body wt/day for 5 days) did not improve their insulin tolerance. After functional evisceration, the blood sugar fall (if expressed as percentage of the initial level) was significantly slower in underfed than in ad libitum-fed rats. However, the decline of the blood sugar level appeared to be more markedly enhanced by insulin in the underfed animals.

Effect of X-irradiation on hepatic carbohydrate enzymes in control and hypophysectomized rats

1959 ◽  
Vol 197 (6) ◽  
pp. 1284-1290 ◽  
Author(s):  
George Weber ◽  
Antonio Cantero
Keyword(s):  
Blood Sugar ◽  
Metabolic Response ◽  
Liver Glycogen ◽  
Enzymatic Activities ◽  
Metabolic Reaction ◽  
Phosphogluconate Dehydrogenase ◽  
Hypophysectomized Rats ◽  
X Irradiation ◽  
Total Body ◽  
Carbohydrate Enzymes

The sequence of metabolic events was investigated in rats for 8 days after exposure to 600 r total-body x-irradiation. The preirradiation studies showed that in hypophysectomized animals 18 hours of fasting reduced the activities of enzymes involved in glucose-6-phosphate utilization indicating that the hypophysis is involved in the physiological maintenance of these enzymatic activities. In control animals after irradiation fasting blood sugar and liver glycogen increased reaching a peak at 3 days and returning to normal range at 8 days postirradiation. Hepatic phosphohexoseisomerase and phosphoglucomutase activities indicated the presence of an increased glycogenesis and gluconeogenesis. Liver 6-phosphogluconate dehydrogenase activity increased to almost double the preirradiation value and stayed at this level during the whole postirradiation period. Glucose-6-phosphatase activity was not affected by irradiation. In hypophysectomized animals after irradiation blood sugar, liver glycogen and most enzymatic activities remained essentially in the preirradiation level, indicating that hypophysectomy abolished the characteristic carbohydrate metabolic response to radiation. The deficient metabolic reaction of hypophysectomized animals was correlated with the increased mortality rate in this group.

Effects of glucagon with or without insulin administration on liver glycogen metabolism

1995 ◽  
Vol 269 (2) ◽  
pp. E231-E238 ◽  
Author(s):  
N. Ercan ◽  
M. C. Gannon ◽  
F. Q. Nuttall
Keyword(s):  
Plasma Glucose ◽  
Glycogen Phosphorylase ◽  
Glycogen Metabolism ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Insulin Administration ◽  
Similar Increase ◽  
Glycogen Concentration ◽  
Ad Libitum ◽  
Glucagon And Insulin

Rats fed ad libitum were given insulin alone (4 U/kg), glucagon alone (25 micrograms/kg), or insulin and glucagon sequentially. Phosphorylase a and synthase R activities, hepatic glycogen, uridine diphosphoglucose, inorganic phosphate (Pi), and plasma glucose, lactate, glucagon, and insulin concentrations were determined over the subsequent 40 min. In separate animals, muscle extraction of 2-deoxy-D-[3H]glucose also was determined. After glucagon administration, glycogen phosphorylase a and plasma glucose were increased within 5 min. However, the glycogen concentration did not decrease for 20 min. Glucagon administration to rats pretreated with insulin stimulated a similar increase in phosphorylase a activity. Again, glycogen was not degraded for 20 min. After insulin only, glycogen concentration remained unchanged. Plasma glucose decreased as expected. In each group, muscle extraction of 2-deoxy-D-[3H]glucose increased compared with the controls (P < 0.05). In summary, glucagon and/or insulin administration did not stimulate significant glycogen degradation for 20 min, even though phosphorylase was activated. The mechanism remains to be determined.

Formation of gluconeogenic precursors in rat skeletal muscle during fasted-refed transition

1990 ◽  
Vol 259 (4) ◽  
pp. E513-E516
Author(s):  
M. N. Goodman ◽  
R. Dietrich ◽  
P. Luu
Keyword(s):  
Skeletal Muscle ◽  
Blood Lactate ◽  
Muscle Metabolism ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Indirect Pathway ◽  
Rat Skeletal Muscle ◽  
Fasted State ◽  
Glycogen Repletion ◽  
Fasted Rats

During the fasted-refed transition, hepatic glycogen repletion from glucose can occur by the direct and indirect pathway. In the indirect pathway, glucose is first metabolized to 3-carbon intermediates that then are converted in the liver to glucose 6-phosphate via the gluconeogenic pathway before conversion to glycogen. The present study evaluated whether skeletal muscle is a major source of 3-carbon intermediates (i.e., lactate, pyruvate, and alanine) during refeeding of 1-day fasted rats. Arteriovenous differences for lactate, pyruvate, and alanine across the anesthetized rat hindlimbs were used to evaluate muscle metabolism in the fed, fasted, and refed state. In the fasted state, liver glycogen was depleted, and muscle released 3-carbon intermediates. One hour after refeeding, hepatic glycogen was 30% repleted, and blood lactate, pyruvate, and alanine increased. Despite this, the release of alanine by muscle diminished at this time and lactate was removed. At 4 h after refeeding, 3-carbon intermediates were all released by hindlimb tissue but in an amount not greater than in the fasted state. Overall, these results suggest that skeletal muscle in the rat is not a major source of 3-carbon precursors for early postprandial hepatic glycogen repletion via the indirect pathway, nor is the rise in 3-carbon intermediates in blood during refeeding caused by their increased output by muscle.

scholarly journals Pregnancy and pentobarbital anaesthesia modify hepatic synthesis of acylglycerol glycerol and glycogen from gluconeogenic precursors during fasting in rats

1988 ◽  
Vol 256 (2) ◽  
pp. 487-491 ◽  
Author(s):  
A Zorzano ◽  
E Herrera
Keyword(s):  
Late Pregnancy ◽  
Liver Glycogen ◽  
Control Group ◽  
Hepatic Glycogen ◽  
Dihydroxyacetone Phosphate ◽  
Pregnant Rats ◽  
Glucose Synthesis ◽  
Marked Accumulation ◽  
Fasted Rats ◽  
Hepatic Synthesis

1. Incorporation of gluconeogenic precursors into blood glucose and hepatic glycogen and acylglycerol glycerol was examined in 24 h-fasted virgin rats by using a flooding procedure for substrate administration. At 10 min after their intravenous injection, the conversion of alanine or glycerol into liver glycogen or acylglycerol glycerol was proportional to glucose synthesis. 2. In 24 h-fasted 21-day-pregnant rats, the incorporation of alanine and glycerol into hepatic acylglycerol glycerol was markedly enhanced compared with the control group. In addition, during fasting at late pregnancy, the proportion of substrates directed to acylglycerol glycerol as compared with the fraction incorporated into glucose was augmented. 3. In pentobarbital-treated fasted rats, the incorporation of both alanine and pyruvate into circulating glucose and into hepatic glycogen and acylglycerol glycerol was increased. Pentobarbital treatment increased the proportion of substrates incorporated into liver glycogen, compared with the fraction appearing in circulating glucose. These changes were concomitant with a marked accumulation of glycogen. 4. The data indicate that, during fasting, gluconeogenesis provides glucose as well as hepatic glycogen and acylglycerol glycerol, independently of whether the substrates enter gluconeogenesis at the level of pyruvate or dihydroxyacetone phosphate.

Oxidation to C14O2 and conversion to fatty acids of C14-glucose in livers of normal, fasted and x-irradiated rats

1959 ◽  
Vol 197 (3) ◽  
pp. 674-676 ◽  
Author(s):  
John G. Coniglio ◽  
Deborah L. Cate ◽  
Bryant Benson ◽  
Granville W. Hudson
Keyword(s):  
Fatty Acids ◽  
Liver Slices ◽  
X Irradiation ◽  
Per Se ◽  
Total Body ◽  
And Control ◽  
Oxidation Of Glucose

Oxidation of glucose-1-C14 and of glucose-6-C14 to C14O2 was greater in slices and homogenates of livers of rats given 1000 r total-body x-irradiation and fasted 24–48 hours than in their nonirradiated fasted controls. The ratio: C14O2 from glucose-6-C14/C14O2 from glucose-1-C14 was not altered in homogenates either by fasting or by x-irradiation. In liver slices, the ratio was increased by fasting, per se, but was not affected by x-irradiation. In rats weighing 350–400 gm, hepatic conversion of glucose-1-C14 and of glucose-6-C14 to fatty acids was greater in the irradiated fasted animals than in nonirradiated fasted controls although the ratio: C14-fatty acids from glucose-6-C14/C14-fatty acids from glucose-1-C14 was not affected by irradiation. In rats weighing 160–200 gm, no difference in lipogenesis from either glucose-1-C14 or glucose-6-C14 was apparent between irradiated and control rats.

The Effect of Total-Body X-Irradiation on Fatty Acids of Testes of Rats

1963 ◽  
Vol 20 (3) ◽  
pp. 372 ◽  
Author(s):  
John G. Coniglio ◽  
F. Bartow Culp ◽  
James Davis ◽  
Wendell Ford ◽  
Frank Windler
Keyword(s):  
Fatty Acids ◽  
X Irradiation ◽  
Total Body
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