Effect of prolonged cold exposure on the glycolytic enzymes of liver and muscle

1960 ◽  
Vol 198 (2) ◽  
pp. 375-380 ◽  
Author(s):  
John P. Hannon ◽  
David A. Vaughan
Keyword(s):  
Muscle Tissue ◽  
Cold Exposure ◽  
Liver Tissue ◽  
Glycolytic Enzymes ◽  
Hexose Monophosphate ◽  
Sprague Dawley ◽  
Cold Effect ◽  
Sprague Dawley Rats ◽  
Free Glucose ◽  
Muscle Phosphorylase

Liver and muscle tissue from male Sprague-Dawley rats, exposed to 5 ± 1°C for 3–4 weeks, were assayed for the activities of selected glycolytic enzymes. When compared to control animals maintained at 25 ± 1°C, the cold-exposed animals showed an increase in liver glucose-6-phosphatase, an increase in liver and muscle glucokinase, a decrease in glucose-6-phosphate and 6-phosphogluconic dehydrogenase in both liver and muscle, and an increase in the rate of pyruvate formation from 3-phosphoglycerate in liver tissue. Assays of liver and muscle phosphoglucomutase, total liver and muscle phosphorylase and phosphorylase a and b in muscle failed to show any cold effect. The results indicate the cold-exposed rat has the enzyme capacities for: an increased utilization of free glucose, an increased glycogenolysis either to free glucose to pyruvate and an increased gluconeogenesis. They also indicate a decreased hexose monophosphate shunt activity. Little evidence could be found to indicate an epinephrine-induced activation of phosphorylase in the cold-exposed animals.

Selective activation of norepinephrine- and epinephrine-secreting chromaffin cells in rat adrenal medulla

1992 ◽  
Vol 263 (3) ◽  
pp. R716-R721 ◽  
Author(s):  
R. R. Vollmer ◽  
A. Baruchin ◽  
S. S. Kolibal-Pegher ◽  
S. P. Corey ◽  
E. M. Stricker ◽  
...  
Keyword(s):  
Cold Exposure ◽  
Chromaffin Cells ◽  
Statistical Significance ◽  
Significant Rise ◽  
Significant Decline ◽  
Synthetic Activity ◽  
Sprague Dawley ◽  
Selective Activation ◽  
Sprague Dawley Rats ◽  
Contrast Exposure

The differential effects of insulin-induced hypoglycemia and cold exposure on adrenal medullary epinephrine (Epi) and norepinephrine (NE) cells were investigated in male Sprague-Dawley rats. In rats fasted overnight, insulin produced a marked hypoglycemia that resulted in a 70% decrease in adrenal medullary Epi content 3 h after the insulin was administered. No change in NE content was observed. Plasma Epi concentration was increased markedly after insulin, with a smaller increment in NE. In contrast, exposure to a 4 degrees C environment selectively reduced adrenal NE content, with the effect reaching statistical significance at 18 h. Cold exposure also led to a significant rise in plasma NE but not Epi. Both insulin-induced hypoglycemia and cold exposure significantly elevated adrenal dopamine, indicating that catecholamine synthesis was stimulated. Further evidence of enhanced catecholamine formation was the observation that inhibition of synthesis with alpha-methyl-p-tyrosine (AMT) greatly augmented the ability of insulin-induced hypoglycemia to selectively reduce adrenal medullary Epi content. Similarly, in cold-exposed animals, AMT pretreatment accelerated the NE depletion so that a significant decline was observed at 3 h. These results support the conclusion that the two major populations of adrenal catecholamine-secreting cells may be preferentially stimulated by different stressors. Moreover, augmented synthetic activity functions to maintain catecholamine stores in both Epi- and NE-secreting cells.

scholarly journals Dietary Garcinol Attenuates Hepatic Pyruvate and Triglyceride Accumulation by Inhibiting P300/CBP-Associated Factor in Mid-to-Late Pregnant Rats

2019 ◽  
Author(s):  
Weilei Yao ◽  
Tongxin Wang ◽  
Jun Xia ◽  
Juan Li ◽  
Xinhong Yu ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
Lipid Synthesis ◽  
Basal Diet ◽  
Isolated Hepatocytes ◽  
Glycolytic Enzyme ◽  
Glycolytic Enzymes ◽  
Sprague Dawley ◽  
Pregnant Rats ◽  
Triglyceride Accumulation ◽  
Sprague Dawley Rats

ABSTRACT Background Increased hepatic glycolysis and lipogenesis are characteristic of pregnancy. Objectives The present study aimed to investigate the mechanism of garcinol on the amelioration of hepatic pyruvate and triglyceride (TG) accumulation in mid-to-late pregnant rats. Methods Forty Sprague-Dawley pregnant rats (aged 9 wk, n = 10/diet) were fed a basal diet (control) or that diet plus garcinol at 100 ppm (Low Gar), 300 ppm (Mid Gar), or 500 ppm (High Gar) for 14 d. The livers were processed for Western blotting analyses and measuring enzymatic activity and pyruvate and TG concentrations. Hepatocytes from other pregnant Sprague Dawley rats were transfected with P300/CBP associating factor (PCAF) short interfering (si)RNAs; hepatocytes from nonpregnant Sprague-Dawley rats with overexpression of PCAF were treated with garcinol (5 μM). The activity and acetylation of upstream stimulatory factor (USF-1) and glycolytic enzymes were analyzed. Results Dietary garcinol significantly decreased (P < 0.05) concentrations of hepatic and plasma TG (27.1–45.8%) and total cholesterol (25.3–49.5%), plasma free fatty acids (24.4–37.8%), and hepatic pyruvate (31.5–43.5%) and lactate (33.4–65.7%) in mid-to-late pregnant rats. Garcinol promoted (P < 0.05) antioxidant capacity in the liver and plasma by 27.4–32.1%. Garcinol downregulated (P < 0.05) lipid synthesis-related enzyme expression by 30.6–85.3% and decreased (P < 0.05) glycolytic enzyme activities by 22.5–74.6% and PCAF activity by 18.6–55.4%. Transfection of PCAF siRNAs to hepatocytes of pregnant rats decreased USF-1 and glycolytic enzyme activities by PCAF; garcinol treatment downregulated (P < 0.05) the acetylation and activities of USF-1 and glycolytic enzymes by 35.6–83.7%. Conclusions Garcinol attenuates hepatic pyruvate and TG accumulation in the liver of mid-to-late pregnant rats, which may be due to downregulating the acetylation of USF-1 and the glycolytic enzymes induced by PCAF in isolated hepatocytes.

Effect of prolonged cold exposure on the gross blood composition of the rat

1959 ◽  
Vol 197 (5) ◽  
pp. 1008-1012 ◽  
Author(s):  
John P. Hannon ◽  
David W. Young
Keyword(s):  
Blood Glucose ◽  
Specific Gravity ◽  
Plasma Protein ◽  
Cold Exposure ◽  
Plasma Lipids ◽  
Total Plasma ◽  
Sprague Dawley ◽  
Nonprotein Nitrogen ◽  
Protein Levels ◽  
Sprague Dawley Rats

One month's cold exposure (5 ± 1 °C) of male Sprague-Dawley rats induced a slight, but significant, increase in hemoglobin levels but had no effect on the hematocrit. Fasting for 24 hours, although not altering the hemoglobin concentrations of either the control or the cold-exposed animals, did produce a slight lowering of the hematocrit. Cold exposure also resulted in a plasma dilution as indicated by a significant increase in plasma water, and significant decreases in plasma specific gravity and plasma protein levels. Fasting superimposed a further reduction in plasma protein levels under both control and cold-exposed conditions. The levels of blood glucose and total plasma lipids were unaltered by cold exposure but each was significantly reduced by fasting. Significant increases in the nonprotein nitrogen, phospholipid, cholesterol and ketone levels were observed in cold-exposed, nonfasted animals. Superimposed on these changes, fasting produced a decrease in the levels of nonprotein nitrogen and phospholipids and an increase in the level of ketones. It had no effect on the level of cholesterol. Fasting of the cold-exposed animals led to greater reductions in plasma nonprotein nitrogen and phospholipids and a smaller increase in blood ketones as compared to controls.

Acute alcohol produces hypoxia directly in rat liver tissue in vivo: role of Kupffer cells

1996 ◽  
Vol 271 (3) ◽  
pp. G494-G500 ◽  
Author(s):  
G. E. Arteel ◽  
J. A. Raleigh ◽  
B. U. Bradford ◽  
R. G. Thurman
Keyword(s):  
Rat Liver ◽  
Kupffer Cells ◽  
Large Dose ◽  
Liver Tissue ◽  
Ethanol Metabolism ◽  
Isolated Perfused Rat Liver ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Hypoxia Marker

Previous studies using liver slices and isolated perfused rat liver have suggested that ethanol causes hypoxia by increasing oxygen consumption. However, ethanol also increases blood flow to the liver, a phenomenon that may counteract the effects of hypermetabolism by increasing oxygen delivery. Thus whether ethanol causes hypoxia in vivo remains unclear. To clarify this important point, female Sprague-Dawley rats (100-125 g) simultaneously received pimonidazole (120 mg/kg ip), a 2-nitroimidazole hypoxia marker, and one large dose of ethanol (5 g/kg ig), which increase hepatic oxygen uptake dramatically and elevate ethanol metabolism (swift increase in alcohol metabolism) in 2-3 h. After 2 h, ethanol significantly increased the accumulation of bound pimonidazole in pericentral regions of the liver lobule. Treatment of animals with the Kupffer cell-specific toxicant, GdCl3 (10 mg/kg iv, 24 h before experiment), blocked ethanol-induced increases in pimonidazole binding. It is concluded that one large dose of ethanol causes pericentral hypoxia in rat liver tissue in vivo and that Kupffer cells are involved.

scholarly journals Cardiovascular and metabolic responses of hypertensive and normotensive rats to one week of cold exposure

2000 ◽  
Vol 279 (4) ◽  
pp. R1486-R1494 ◽  
Author(s):  
J. B. Chambers ◽  
T. D. Williams ◽  
A. Nakamura ◽  
R. P. Henderson ◽  
J. M. Overton ◽  
...  
Keyword(s):  
Cold Exposure ◽  
Energy Homeostasis ◽  
Cardiovascular Responses ◽  
General Concept ◽  
Sprague Dawley ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Sprague Dawley Rats ◽  
Rapid Changes ◽  
Secondary Consequence

Challenges to energy homeostasis, such as cold exposure, can have consequences for both metabolic and cardiovascular functioning. We hypothesized that 1-wk cold exposure (4°C) would produce concurrent increases in metabolic rate (V˙o 2; indirect calorimetry), heart rate (HR), and mean arterial blood pressure (MAP) measured by telemetry. In the initial hours of change in ambient temperature (Ta), both spontaneously hypertensive rats (SHRs) and normotensive Sprague-Dawley rats showed rapid increases (in cold) or decreases (in rewarming) of V˙o 2, HR, and MAP, although the initial changes in MAP and HR were more exaggerated in SHRs. Throughout cold exposure, HR,V˙o 2, food intake, and locomotor activity remained elevated but MAP decreased in both strains, particularly in the SHR. During rewarming, all measures normalized quickly in both strains except MAP, which fell below baseline (hypotension) for the first few days. The results indicate that variations of Taproduce rapid changes in a suite of cardiovascular and behavioral responses that have many similarities in hypertensive and normotensive strains of rats. The findings are consistent with the general concept that the cardiovascular responses to cold exposure in rats are closely related to and perhaps a secondary consequence of the mechanisms responsible for increasing heat production.

Interrelationships of diet and cold exposure on selected liver glycolytic enzymes

1961 ◽  
Vol 201 (1) ◽  
pp. 33-36 ◽  
Author(s):  
David A. Vaughan ◽  
John P. Hannon ◽  
Lucile N. Vaughan
Keyword(s):  
Phosphatase Activity ◽  
Cold Exposure ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Glycolytic Enzymes ◽  
Appreciable Effect ◽  
High Carbohydrate ◽  
Free Glucose ◽  
Fat Diets ◽  
Glucose 6 Phosphate Dehydrogenase

The effect of a 28-day cold exposure (4 ± 1 C) on selected glycolytic enzymes of the liver was studied in rats subsisting on carbohydrate free diets high in fat or protein and on a 65% glucose diet. Cold exposure increased glucose-6-phosphatase activity on all diets, but had an appreciable effect on glucokinase activity only in the rats fed high carbohydrate diets. The activity of phosphorylase was not affected by cold. "Pyruvate formation," like glucose-6-phosphatase activity, was increased significantly in all dietary groups by cold exposure. The extremely low activity of glucose-6-phosphate dehydrogenase in the rats fed high fat diets was unaffected by cold exposure. These results are interpreted to mean that, on a carbohydrate free diet, imposition of cold leads to increased reversal of pyruvate formation which is reflected in increased production of free glucose, whereas hexose monophosphate shunt activity and glycogenesis remain unaffected. Even on a high carbohydrate diet, the capacity for hepatic glucose production appears to be increased, possibly as a result of increased periodic demands on the part of extrahepatic tissues.

Evidence of environmental influence on the development of thermoregulation in the rat

1981 ◽  
Vol 59 (2) ◽  
pp. 91-95 ◽  
Author(s):  
A. V. Ferguson ◽  
W. L. Veale ◽  
K. E. Cooper
Keyword(s):  
Cold Exposure ◽  
Temperature Regulation ◽  
Thermal Environment ◽  
Environmental Influence ◽  
Sprague Dawley ◽  
Thermoregulatory Responses ◽  
Sprague Dawley Rat ◽  
Sprague Dawley Rats ◽  
Colonic Temperature ◽  
And Control

Sprague–Dawley rats were raised in an environmentally controlled room at 33 °C. Thermoregulatory responses of animals reared in this way were compared with those of control and warm-acclimated rats. Warm-reared animals demonstrated a significantly greater fall in colonic temperature during cold exposure when compared with both warm-acclimated (p < 0.01) and control (p < 0.001) animals. Warm-reared animals also show a modified response to central infusion of noradrenaline; they produce a hyperthermia in contrast with the hypothermia observed in control and warm-acclimated rats. These results suggest that the early thermal environment may modify the development of temperature regulation in the Sprague–Dawley rat in a way different from the normal acclimation process.

The effects of chronic cold exposure on diurnal corticosterone and aldosterone rhythms in Sprague-Dawley rats

1993 ◽  
Vol 54 (2) ◽  
pp. 363-367 ◽  
Author(s):  
Mary Ellen Bligh-Tynan ◽  
Seema A Bhagwat ◽  
Thomas W Castonguay
Keyword(s):  
Cold Exposure ◽  
Sprague Dawley ◽  
Sprague Dawley Rats
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