scholarly journals Lipolytic response of adipose tissue and metabolic adaptations to long periods of fasting in red tilapia (Oreochromis sp., Teleostei: Cichlidae)

2016 ◽  
Vol 88 (3 suppl) ◽  
pp. 1743-1754 ◽  
Author(s):  
WALTER DIAS JUNIOR ◽  
AMANDA M. BAVIERA ◽  
NEUSA M. ZANON ◽  
VICTOR D. GALBAN ◽  
MARIA ANTONIETA R. GARÓFALO ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Plasma Glucose ◽  
Lipolytic Activity ◽  
Phosphodiesterase Inhibitor ◽  
Liver Glycogen ◽  
Camp Phosphodiesterase ◽  
Red Tilapia ◽  
Glucose Levels ◽  
Plasma Ffa

ABSTRACT Adaptive changes of carbohydrate and lipid metabolism induced by 7, 15, 30, 60, 90, 150 and 200 days of fasting were investigated in red tilapia (Oreochromis sp.). Plasma glucose, lactate and free fatty acids (FFA) levels, liver and muscle glycogen and total lipid contents and rates of FFA release from mesenteric adipose tissue (MAT) were measured. Plasma glucose levels showed significant differences only after 90 days of fasting, when glycemia was 34% lower (50±5mg.dL-1) than fed fish values (74±1mg.dL-1), remaining relatively constant until 200 days of fasting. The content of liver glycogen ("15%) in fed tilapia fell 40% in 7 days of food deprivation. In 60, 90 and 150 days of fasting, plasma FFA levels increased 49%, 64% and 90%, respectively, compared to fed fish values. In agreement with the increase in plasma FFA, fasting induced a clear increase in lipolytic activity of MAT incubated in vitro. Addition of isobutylmethylxanthine (cAMP-phosphodiesterase inhibitor) and isoproterenol (non selective beta adrenergic agonist) to the incubation medium induced a reduction of lipolysis in fasted fish, differently to what was observed in mammal adipose tissue. This study allowed a physiological assessment of red tilapia response to starvation.

scholarly journals Carbohydrate ingestion does not alter skeletal muscle AMPK signaling during exercise in humans

2006 ◽  
Vol 291 (3) ◽  
pp. E566-E573 ◽  
Author(s):  
Robert S. Lee-Young ◽  
Matthew J. Palmer ◽  
Kelly C. Linden ◽  
Kieran LePlastrier ◽  
Benedict J. Canny ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Glucose ◽  
Plasma Epinephrine ◽  
Muscle Lactate ◽  
Carbohydrate Ingestion ◽  
Ampk Signaling ◽  
Glucose Levels ◽  
Exercise Induced ◽  
Exercise In Humans

There is evidence that increasing carbohydrate (CHO) availability during exercise by raising preexercise muscle glycogen levels attenuates the activation of AMPKα2 during exercise in humans. Similarly, increasing glucose levels decreases AMPKα2 activity in rat skeletal muscle in vitro. We examined the effect of CHO ingestion on skeletal muscle AMPK signaling during exercise in nine active male subjects who completed two 120-min bouts of cycling exercise at 65 ± 1% V̇o2 peak. In a randomized, counterbalanced order, subjects ingested either an 8% CHO solution or a placebo solution during exercise. Compared with the placebo trial, CHO ingestion significantly ( P < 0.05) increased plasma glucose levels and tracer-determined glucose disappearance. Exercise-induced increases in muscle-calculated free AMP (17.7- vs. 11.8-fold), muscle lactate (3.3- vs. 1.8-fold), and plasma epinephrine were reduced by CHO ingestion. However, the exercise-induced increases in skeletal muscle AMPKα2 activity, AMPKα2 Thr172 phosphorylation and acetyl-CoA Ser222 phosphorylation, were essentially identical in the two trials. These findings indicate that AMPK activation in skeletal muscle during exercise in humans is not sensitive to changes in plasma glucose levels in the normal range. Furthermore, the rise in plasma epinephrine levels in response to exercise was greatly suppressed by CHO ingestion without altering AMPK signaling, raising the possibility that epinephrine does not directly control AMPK activity during muscle contraction under these conditions in vivo.

Increased in vitro fatty acid supply and cellular transport capacities in cold-acclimated ducklings (Cairina moschata)

1998 ◽  
Vol 275 (3) ◽  
pp. R683-R690 ◽  
Author(s):  
Christophe Bénistant ◽  
Claude Duchamp ◽  
Frédérique Cohen-Adad ◽  
Jean-Louis Rouanet ◽  
Hervé Barré
Keyword(s):  
Adipose Tissue ◽  
Gastrocnemius Muscle ◽  
Lipolytic Activity ◽  
Binding Capacity ◽  
Cellular Transport ◽  
Transport Capacity ◽  
Nonesterified Fatty Acids ◽  
Cairina Moschata

In cold-acclimated (CA) birds, lipids play a crucial role in regulatory thermogenesis by acting both as substrates for and activators of thermogenic processes. The capacity to supply lipids to thermogenic tissues, which could limit cold thermogenesis, was assessed in CA ducklings (5 wk old, 4°C) and compared with thermoneutral controls (TN, 25°C). In CA ducklings, basal lipolytic activity of adipose tissue fragments was higher (202 ± 9 vs. 130 ± 14 nmol glycerol released ⋅ 100 mg tissue−1 ⋅ h−1, +55%) than in TN controls, while glucagon had a much higher stimulatory effect (+140 to +500% depending on dose). This was consistent with increased plasma levels of nonesterified fatty acids (FA, +57%) and glycerol (+31%) in vivo. In vitro endothelial lipase activity per organ was higher in CA than in TN ducklings in red gastrocnemius muscle (6.3 ± 0.6 vs. 3.5 ± 0.3 μeq nonesterified FA released per hour, +80%) and liver (+55%). The intracellular FA-binding capacity of (12–18 kDa) proteins was higher in gastrocnemius muscle (+43%) and liver (+74%) from CA ducklings. In gastrocnemius, it was linked to a higher content (21 ± 2 vs. 15 ± 2 μg/mg protein, +37%) of an intracellular 15.4-kDa FA-binding protein. These in vitro results indicate that coordinated increases in FA supply from adipose tissue, cellular uptake of lipoprotein-derived FA, and intracellular FA transport capacity occur in CA ducklings endowed with higher thermogenic capacity and cold endurance.

Effects of Acute Exposure to Bleached Kraft Pulpmill Effluent on Carbohydrate Metabolism of Juvenile Coho Salmon (Oncorhynchus kisutch) During Rest and Exercise

1975 ◽  
Vol 32 (6) ◽  
pp. 753-760 ◽  
Author(s):  
D. J. McLeay ◽  
D. A. Brown
Keyword(s):  
Plasma Glucose ◽  
Muscle Glycogen ◽  
Coho Salmon ◽  
Liver Glycogen ◽  
Plasma Lactate ◽  
Mean Values ◽  
Glucose Levels ◽  
Lactate Levels ◽  
Sugar Levels ◽  
Glycogen Stores

In the static study (no exercise), liver glycogen stores were unchanged during 12-h exposure to 0.8 of the 96-h LC50; longer exposures caused a progressive decrease to levels one fifth those of controls at 72 h. Plasma glucose levels in fish held in 0.8 LC50 effluent for 3–96 h were elevated; at 96 h, glucose had increased threefold. Mean values for plasma lactate were elevated significantly at 3, 6, 24, 72, and 96 h.In the exercise (swimming one body length per second)–rest study, muscle glycogen levels decreased 53–78% during exercise in water or effluent (0.7 LC50) for 4–12 h, and did not recover during 12-h rest in water. Muscle glycogen for fish exercised for 12 h in effluent and then rested for 4 or 12 h in effluent was lower compared to values for fish exercised in effluent and then rested in water. There was no difference in liver glycogen levels offish exercised in effluent or water for 4–12 h. Values of liver glycogen for fish exercised in effluent for 12 h and then rested for 4, 8, or 12 h in effluent decreased 60–70% compared to fish exercised in water for 12 h and then rested in water and by 55–65% from fish exercised in effluent for 12 h and rested in water for 4–12 h. Plasma glucose levels were elevated one- to fourfold during exercise in water or effluent. Fish resting in water for 4, 8, or 12 h following exercise in water had relatively stable glucose levels; whereas for fish exercised and then rested in effluent the glucose levels increased twofold during resting. Plasma lactate levels were elevated five- to sixfold during exercise in water or effluent for 4–12 h, declining to values 1–2 times those of stock fish within 4-h rest. Plasma lactate levels for fish exercised in effluent and then rested in effluent or water were continually higher than those for fish exercised and rested in water.It was concluded that measurement of carbohydrate metabolites, particularly blood sugar levels, in unexercised fish could prove useful as a rapid method for measuring toxicity of pulpmill effluents and other pollutants.

AN EXTRA-ADRENAL ACTION OF ADRENOCORTICOTROPHIN: PHYSIOLOGICAL INDUCTION OF LIPOLYSIS BY SECRETION OF ADRENOCORTICOTROPHIN IN OBESE RABBITS

1979 ◽  
Vol 81 (3) ◽  
pp. 281-290 ◽  
Author(s):  
M. LAFONTAN ◽  
R. AGID
Keyword(s):  
Adipose Tissue ◽  
Pituitary Hormone ◽  
Blocking Drug ◽  
Nacl Solution ◽  
Plasma Acth ◽  
Lipid Mobilization ◽  
Physiological Importance ◽  
Plasma Ffa

The effect of minor stressful stimuli (saline infusions or venepunctures) on lipid mobilization (estimated by plasma free fatty acids (FFA) and glycerol levels) was studied in two strains of conscious rabbits of various ages. Infusions of 0·9% (w/v) NaCl solution induced a prompt increase of FFA levels in naturally obese rabbits while this effect was absent in younger lighter animals. Administration of propranolol (a β-adrenoceptor blocking drug) beforehand did not prevent lipid mobilization. Adipose tissue in vitro was completely unresponsive to the lipid mobilizing action of adrenaline. The initial output of ACTH induced by stressful stimuli was quickly followed by the increase in the plasma concentration of FFA. A highly significant correlation (r = 0·84 or 0·85; P< 0·01) existed between plasma ACTH and FFA levels 30 and 60 min after the start of stress. Dexamethasone completely prevented lipid mobilization while adipose tissue in vivo and in vitro responded strongly to ACTH. Consequently the lack of response of plasma FFA concentrations in corticosteroid-treated rabbits seemed to be linked to the failure of the pituitary gland to mobilize ACTH rather than to the unresponsiveness of adipose tissue to the pituitary hormone. Our data indicate that in the rabbit, under conditions of stress, ACTH is of greater physiological importance than catecholamines in the control of lipolysis.

scholarly journals Simulated Microgravity Increases β-Adrenergic Lipolysis in Human Adipose Tissue1

1998 ◽  
Vol 83 (2) ◽  
pp. 619-625
Author(s):  
P. Barbe ◽  
J. Galitzky ◽  
I. De Glisezinski ◽  
D. Riviere ◽  
C. Thalamas ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipolytic Activity ◽  
Nervous Activity ◽  
Bed Rest ◽  
Sympathetic Nervous Activity ◽  
Glycerol Concentration ◽  
Dibutyryl Camp ◽  
Adrenergic Response ◽  
Cgp 12177

The effect of a sustained decrease in sympathetic nervous activity, achieved through 5-day head-down bed rest (HDBR), on the β-adrenergic lipolytic activity of sc adipose tissue was studied in eight healthy men. The in situ β-adrenoceptor (AR) sensitivity was studied using the microdialysis method. Local perfusion of increasing concentrations of isoprenaline showed an increased β-AR sensitivity to lipolysis (assessed by extracellular glycerol concentration) and to vascular tone (assessed by the ethanol clearance). The adrenergic sensitivity of isolated adipocytes was studied in vitro. Basal lipolysis and the response to nonselective (isoprenaline) or selective (dobutamine, terbutaline, and CGP 12177) β-AR agonists were increased after HDBR as was the lipolytic effect of dibutyryl cAMP. When data were expressed as a percentage of the dibutyryl cAMP effect to rule out the postreceptor events, basal and lipolytic responses toβ -AR agonists where similar before and during HDBR. Theα 2-AR-mediated antilipolytic effects of adrenaline were not modified. Lymphocyte β-AR number was unchanged during HDBR. Our results demonstrate that a sustained sympathoinhibition induces an increase in the lipolytic β-adrenergic response in adipose tissue and suggest that this hypersensitization is linked to an increase in the postreceptor steps of the lipolytic cascade in the adipocyte rather than to changes in β-adrenoceptors.

Shivering thermogenesis and glucose uptake by muscles of normal or diabetic rats

1982 ◽  
Vol 242 (1) ◽  
pp. R109-R115 ◽  
Author(s):  
O. L. Smith ◽  
S. B. Davidson
Keyword(s):  
Glucose Uptake ◽  
Plasma Glucose ◽  
Serum Insulin ◽  
Liver Glycogen ◽  
Diabetic Rats ◽  
Glucose Levels ◽  
Severe Diabetes ◽  
Mild Diabetes ◽  
Fasted Rats ◽  
Shivering Thermogenesis

Acute cold exposure of normal rats (4 degrees C for 24 h) increased food intake, reduced plasma glucose and liver glycogen, caused a small increase in plasma free fatty acids, and lowered serum insulin concentration by 50%. In fasted rats, cold raised fatty acid levels twice as high as in fed. In mild diabetes (40 mg/kg streptozotocin iv) cold reduced glucose levels in blood and urine, but in severe diabetes (90 mg/kg) cold aggravated hyperglycemia and ketonuria. Changes in muscle glucose utilization were also studied, after evisceration (functional hepatectomy) of rats from each group. Uptake was calculated from the fall in plasma glucose concentration during the 4-h period after a load of 50% glucose iv. Cold normally increased uptake 67%, but it failed to do so in fasted rats. In diabetic rats, cold enhanced uptake, but only if the disease were mild or insulin controlled. Sensitivity of uptake to insulin was unaffected by cold. The results suggest that shivering thermogenesis, like exercise, can promote glucose uptake by skeletal muscle, if enough insulin is present to prevent excess mobilization of lipid substrates.

MEAL-EATING AND LIPOGENESIS IN VITRO OF RATS FED A LOW-PROTEIN DIET

1964 ◽  
Vol 42 (5) ◽  
pp. 665-670 ◽  
Author(s):  
J. R. Beaton ◽  
V. Feleki ◽  
A. J. Szlavko ◽  
J. A. F. Stevenson
Keyword(s):  
Adipose Tissue ◽  
Food Intake ◽  
Body Weight Gain ◽  
Liver Glycogen ◽  
Male Rats ◽  
Acetate Incorporation ◽  
Casein Diet ◽  
Low Protein ◽  
Daily Food

The response of male rats to the restriction of food intake to 2 hours each day for 14 to 16 days has been assessed by the measurement of food intakes, body weights, liver glycogen concentrations, and lipogenesis of adipose tissue (C14-acetate incorporation in vitro). The animals were fed either a 20% casein diet (controls) or an isocaloric 5% casein diet. As a consequence of meal-eating, and regardless of dietary protein level, the average daily food intake and body weight gain were decreased whereas the lipogenesis in vitro and liver glycogen concentration were increased in comparison with rats fed ad libitum,which is in agreement with earlier findings using normal diets. These observations suggest that the decreased body fat of rats fed a 5% casein diet is not a consequence of an impaired ability of adipose tissue to synthesize fat.

Adipose tissue lipolytic activity and urinary catecholamine excretion in cold-acclimated piglets

1991 ◽  
Vol 69 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Patrick Herpin ◽  
Roseline Bertin ◽  
Françoise de Marco ◽  
René Portet ◽  
Jean Le Dividich
Keyword(s):  
Adipose Tissue ◽  
Cold Acclimation ◽  
Significant Variation ◽  
Lipolytic Activity ◽  
Nonshivering Thermogenesis ◽  
Urinary Catecholamine ◽  
Energy Substrates ◽  
Ad Libitum ◽  
White Fat

This study was designed to investigate the effect of chronic cold exposure (12 °C for 3 weeks) on catecholamine production and noradrenaline-induced lipolytic rate to further describe thermoregulatory mechanisms in 5- to 8-week-old pigs. Lipolytic activity in white adipose tissue was assessed in vitro while catecholamine production was estimated by measuring noradrenaline, adrenaline, and dopamine levels in 24-h urine samples. Animals were fed ad libitum and food intake was 20% greater in the cold. In control piglets maintained in a 23 °C environment, the addition of increasing amounts of noradrenaline (10−6, 10−5, 10−4 M) stimulates lipolysis (p < 0.05) and enhances the basal lipolytic rate (5.4 μequiv. fatty acids∙120 min−1∙g−1 tissue) by 2.5-, 2.7-, and 3.9-fold, respectively. Three weeks of cold acclimation had no effect on basal lipolytic rate but increased significantly noradrenaline responsiveness: incubation of subcutaneous white fat in the presence of 10−4 M noradrenaline does increase the basal lipolytic rate by sixfold. Noradrenaline effects were maximally activated by theophylline. Daily dopamine and noradrenaline excretions (3 – 10 μg/24 h) were increased significantly (up to eightfold) after 10 days of cold acclimation. By contrast, adrenaline excretion was quite low (0.6 – 1.6 μg/24 h) and showed no significant variation with time. It is likely that these hormonal and biochemical modifications play a prominent part in the mechanism of cold acclimation in the piglet. Their significance in the development of shivering and nonshivering thermogenesis is discussed in relation to the supply of energy substrates to the fatty acid utilizing tissues and to the possible uncoupling effect of free fatty acids.Key words: pigs, thermogenesis, cold, catecholamines, lipolysis.

scholarly journals Prevention of in Vitro Lipolysis by Tetrahydrolipstatin

2000 ◽  
Vol 46 (7) ◽  
pp. 950-954 ◽  
Author(s):  
Michael Krebs ◽  
Harald Stingl ◽  
Peter Nowotny ◽  
Daniel Weghuber ◽  
Martin Bischof ◽  
...  
Keyword(s):  
Room Temperature ◽  
Storage Temperature ◽  
Lipolytic Activity ◽  
Accurate Determination ◽  
Plasma Concentrations ◽  
Metabolic Effects ◽  
In Vitro Lipolysis ◽  
Plasma Ffa ◽  
Plasma Ffas

Abstract Background: Metabolic effects of free fatty acids (FFAs) frequently are tested using combined infusion of triglycerides and heparin, which stimulates lipolysis in vivo. Ongoing in vitro lipolysis, however, probably produces falsely high plasma FFA concentrations under these conditions. Therefore, this study aims to assess the efficacy of tetrahydrolipstatin (THL) in inhibiting plasma lipolytic activity and to improve plasma FFA determination. Methods: Plasma concentrations of FFAs and glycerol were measured in five healthy subjects in the presence and absence of THL. Blood was drawn at baseline, during infusion of a triglyceride emulsion (1.5 mL/min), and during infusion of triglycerides plus heparin (0.2 IU · kg−1 · min−1). In addition, the effects of storage temperature of the samples were analyzed. Results: In samples frozen immediately after collection, plasma FFAs were 28% lower in the presence of THL than in its absence (P = 0.008). When THL-free plasma was incubated for 3 h on ice or at room temperature, plasma FFAs were 22% (P = 0.02) and 91% (P = 0.0004) higher, respectively, than in samples frozen immediately. The addition of THL blunted temperature-dependent in vitro lipolysis by 88% (P &lt;0.01) and 89% (P &lt;0.001) after incubation on ice and at room temperature, respectively. Changes in plasma glycerol concentrations exhibited similar behavior. Conclusions: THL, which is safe and easy to handle, is a potent inhibitor of in vitro lipolysis and could, therefore, be added to blood samples drawn during triglyceride/heparin infusions to allow more accurate determination of plasma FFA concentrations.

Control of adipose tissue lipolysis in ectotherm vertebrates

1992 ◽  
Vol 263 (4) ◽  
pp. R857-R862 ◽  
Author(s):  
R. H. Migliorini ◽  
J. S. Lima-Verde ◽  
C. R. Machado ◽  
G. M. Cardona ◽  
M. A. Garofalo ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Adenylate Cyclase ◽  
Lipolytic Activity ◽  
Adenylate Cyclase System ◽  
Triacylglycerol Lipase ◽  
Membrane Bound ◽  
Adipose Tissue Lipolysis ◽  
Toad Bufo

Lipolytic activity of fish (Hoplias malabaricus), toad (Bufo paracnemis), and snake (Philodryas patagoniensis) adipose tissue was investigated in vivo and in vitro. Catecholamines or glucagon did not affect the release of free fatty acids (FFA) by incubated fish and toad adipose tissue. Catecholamines also failed to activate snake adipose tissue lipolysis, which even decreased in the presence of epinephrine. However, glucagon stimulated both the lipolytic activity of reptilian tissue in vitro and the mobilization of FFA to plasma when administered to snakes in vivo. The release of FFA from incubated fish, amphibian, and reptilian adipose tissue increased markedly in the presence of cAMP or xanthine derivatives, inhibitors of phosphodiesterase. Forskolin or fluoride, activators of specific components of the adenylate cyclase system, strongly stimulated toad adipose tissue lipolysis. The data suggest that adipocyte triacylglycerol lipase of ectotherm vertebrates is activated by a cAMP-mediated phosphorylation and that the organization of the membrane-bound adenylate cyclase system is similar to that of mammals.

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