Activation of α2-adrenergic receptors blunts epinephrine-induced lipolysis in subcutaneous adipose tissue during a hyperinsulinemic euglycemic clamp in men

2003 ◽  
Vol 285 (3) ◽  
pp. E599-E607 ◽  
Author(s):  
Vladimir Stich ◽  
Tereza Pelikanova ◽  
Petr Wohl ◽  
Coralie Sengenès ◽  
Alexia Zakaroff-Girard ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Adrenergic Receptors ◽  
Glycerol Concentration ◽  
Time Intervals ◽  
Subcutaneous Abdominal Adipose Tissue ◽  
Subcutaneous Adipose ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Male Subjects

The aim of this study was to investigate whether hyperinsulinemia modifies adrenergic control of lipolysis, with particular attention paid to the involvement of antilipolytic α2-adrenergic receptors (AR). Eight healthy male subjects (age: 23.9 ± 0.9 yr; body mass index: 23.8 ± 1.9) were investigated during a 6-h euglycemichyperinsulinemic clamp and in control conditions. Before and during the clamp, the effect of graded perfusions of isoproterenol (0.1 and 1 μM) or epinephrine (1 and 10 μM) on the extracellular glycerol concentration in subcutaneous abdominal adipose tissue was evaluated by using the microdialysis method. Both isoproterenol and epinephrine induced a dose-dependent increase in extracellular glycerol concentration when infused for 60 min through the microdialysis probes before and during hours 3 and 6 of the clamp. The catecholamine-induced increase was significantly lower during the clamp than before it, with the inhibition being more pronounced in hour 6 of the clamp. Isoproterenol (1 μM)-induced lipolysis was reduced by 28 and 44% during hours 3 and 6 of the clamp, respectively, whereas the reduction of epinephrine (100 μM)-induced lipolysis was significantly greater (by 63 and 70%, P < 0.01 and P < 0.04, respectively) during the same time intervals. When epinephrine was infused in combination with 100 μM phentolamine (a nonselective α-AR antagonist), the inhibition of epinephrine (10 μM)-induced lipolysis was only of 19 and 40% during hours 3 and 6 of the clamp, respectively. The results demonstrate that, in situ, insulin counteracts the epinephrine-induced lipolysis in adipose tissue. The effect involves 1) reduction of lipolysis stimulation mediated by the β-adrenergic pathway and 2) the antilipolytic component of epinephrine action mediated by α2-ARs.

Lipolysis in human adipose tissue during exercise: comparison of microdialysis and a-v measurements

2002 ◽  
Vol 92 (3) ◽  
pp. 1310-1316 ◽  
Author(s):  
Kai Henrik Wiborg Lange ◽  
Jeanne Lorentsen ◽  
Fredrik Isaksson ◽  
Lene Simonsen ◽  
Jens Bülow ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Steady State ◽  
Subcutaneous Adipose Tissue ◽  
Human Adipose Tissue ◽  
Glycerol Concentration ◽  
Early Exercise ◽  
Adipose Tissue Lipolysis ◽  
Subcutaneous Abdominal Adipose Tissue ◽  
Subcutaneous Adipose

Subcutaneous adipose tissue lipolysis was studied in vivo by Fick's arteriovenous (a-v) principle using either calculated (microdialysis) or directly measured (catheterization) adipose tissue venous glycerol concentration. We compared results during steady-state (rest and prolonged continuous exercise), as well as during non-steady-state (onset of exercise and early exercise) experimental settings. Fourteen healthy women [age: 74 ± 1 (SE) yr] were studied at rest and during 60-min continuous bicycling at 60% of peak O2 uptake. Calculated and measured subcutaneous abdominal adipose tissue venous glycerol concentrations increased substantially from rest to exercise but were similar both at rest and during later stages of exercise. In contrast, during the initial ∼40 min of exercise, calculated glycerol concentration was significantly lower (∼40%) than measured adipose tissue venous glycerol concentration. Despite several methodological limitations inherent to both techniques, the results strongly suggest that microdialysis and catheterization provide similar estimates of subcutaneous adipose tissue lipolysis in steady-state experimental settings like rest and continuous prolonged exercise. However, during shorter periods of exercise (<40 min), the results from the two techniques may differ quantitatively in the studied subjects. Caution should, therefore, be taken when lipolysis is evaluated, based on results obtained by the two techniques under non-steady-state conditions.

scholarly journals Effect of an Endurance and Strength Mixed Circuit Training on Regional Fat Thickness: The Quest for the “Spot Reduction”

2021 ◽  
Vol 18 (7) ◽  
pp. 3845
Author(s):  
Antonio Paoli ◽  
Andrea Casolo ◽  
Matteo Saoncella ◽  
Carlo Bertaggia ◽  
Marco Fantin ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Subcutaneous Adipose Tissue ◽  
Subcutaneous Fat ◽  
Circuit Training ◽  
Reduced Body ◽  
Before And After ◽  
Traditional Resistance Training ◽  
Subcutaneous Abdominal Adipose Tissue ◽  
Subcutaneous Adipose ◽  
Training Protocol

Accumulation of adipose tissue in specific body areas is related to many physiological and hormonal variables. Spot reduction (SR) is a training protocol aimed to stimulate lipolysis locally, even though this training protocol has not been extensively studied in recent years. Thus, the present study sought to investigate the effect of a circuit-training SR on subcutaneous adipose tissue in healthy adults. Methods: Fourteen volunteers were randomly assigned to spot reduction (SR) or to a traditional resistance training (RT) protocol. Body composition via bioimpedance analysis (BIA) and subcutaneous adipose tissue via skinfold and ultrasound were measured before and after eight weeks of training. Results: SR significantly reduced body mass (p < 0.05) and subcutaneous abdominal adipose tissue (p < 0.05). Conclusions: circuit-training SR may be an efficient strategy to reduce in a localized manner abdominal subcutaneous fat tissue depot.

Lack of antilipolytic effect of lactate in subcutaneous abdominal adipose tissue during exercise

1999 ◽  
Vol 86 (6) ◽  
pp. 1800-1804 ◽  
Author(s):  
François Trudeau ◽  
Sylvain Bernier ◽  
Isabelle de Glisezinski ◽  
François Crampes ◽  
François Dulac ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Subcutaneous Tissue ◽  
Maximal Oxygen Consumption ◽  
Physiological Saline ◽  
Tissue Blood Flow ◽  
Glycerol Concentration ◽  
Abdominal Adipose Tissue ◽  
Glycerol Level ◽  
Good Physical Condition ◽  
Subcutaneous Abdominal Adipose Tissue

The purpose of our study was to evaluate the potential inhibition of adipose tissue mobilization by lactate. Eight male subjects (age, 26.25 ± 1.75 yr) in good physical condition (maximal oxygen uptake, 59.87 ± 2.77 ml ⋅ kg−1 ⋅ min−1; %body fat, 10.15 ± 0.89%) participated in this study. For each subject, two microdialysis probes were inserted into abdominal subcutaneous tissue. Lactate (16 mM) was perfused via one of the probes while physiological saline only was perfused via the other, both at a flow rate of 2.5 μl/min. In both probes, ethanol was also perfused for adipose tissue blood flow estimation. Dialysates were collected every 10 min during rest (30 min), exercise at 50% maximal oxygen consumption (120 min), and recovery (30 min) for the measurement of glycerol concentration. During exercise, glycerol increased significantly in both probes. However, no differences in glycerol level and ethanol extraction were observed between the lactate and control probes. These findings suggest that lactate does not impair subcutaneous abdominal adipose tissue mobilization during exercise.

Cardiac effects of injections of epinephrine into the spinal intermediolateral column

1993 ◽  
Vol 265 (2) ◽  
pp. H633-H641 ◽  
Author(s):  
V. K. Malhotra ◽  
A. Kachroo ◽  
H. N. Sapru
Keyword(s):  
Adrenergic Receptors ◽  
Cardiovascular Responses ◽  
Spinal Level ◽  
Cardiac Effects ◽  
Alpha Adrenergic Receptors ◽  
Small Doses ◽  
The Right ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Stimulation Of

Small doses of epinephrine (0.008, 0.05, and 0.1 pmol, i.e., 20-nl volumes of 0.40, 2.5, and 5 microM solutions) produced a dose-dependent increase in heart rate when micro-injected into the right intermediolateral column (IML) at T2 spinal level. These effects were mediated via alpha 1-adrenergic receptors because prazosin blocked them. The presence of alpha 1-adrenergic receptors at this site was confirmed by microinjections of phenylephrine (a specific agonist for these receptors); phenylephrine elicited tachycardia. Larger doses of epinephrine (320, 2,000, and 3,200 pmol, i.e., 20-nl volumes of 16, 100, and 160 mM solutions) caused bradycardia when microinjected into the IML. These effects were mediated via alpha 2-adrenergic receptors because idazoxan blocked them. The presence of alpha 2-adrenergic receptors at this site was confirmed by microinjections of clonidine (a specific agonist for these receptors); clonidine elicited bradycardia. Injections of the vehicle (20 nl of normal saline containing 0.3% ascorbic acid, pH 7.4) did not evoke a response. Epinephrine, prazosin, or idazoxan did not alter the responses to L-glutamate. None of the doses of epinephrine elicited any response when injected intravenously. The aforementioned results provide pharmacological evidence for the presence of alpha 1- and alpha 2-adrenergic receptors in the IML at T2. Thus a basis is provided for investigating the role, if any, of alpha-adrenergic receptors in the IML in mediating cardiovascular responses elicited by the stimulation of different brain stem areas.

Catecholamine and insulin control of lipolysis in subcutaneous adipose tissue during long-term diet-induced weight loss in obese women

2012 ◽  
Vol 302 (2) ◽  
pp. E226-E232 ◽  
Author(s):  
Katrien Koppo ◽  
Michaela Siklová-Vitková ◽  
Eva Klimčáková ◽  
Jan Polák ◽  
Marie A. Marques ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Subcutaneous Adipose Tissue ◽  
Dietary Intervention ◽  
Glycerol Concentration ◽  
Obese Women ◽  
Low Calorie ◽  
Low Calorie Diet ◽  
Calorie Diet ◽  
Subcutaneous Adipose

The aim of this study was to investigate the evolution of the adrenergic and insulin-mediated regulation of lipolysis during different phases of a 6-mo dietary intervention. Eight obese women underwent a 6-mo dietary intervention consisting of a 1-mo very low-calorie diet (VLCD) followed by a 2-mo low-calorie diet (LCD) and 3-mo weight maintenance (WM) diet. At each phase of the dietary intervention, microdialysis of subcutaneous adipose tissue (SCAT) was performed at rest and during a 3-h hyperinsulinemic euglycemic clamp. Responses of dialysate glycerol concentration (DGC) were determined at baseline and during local perfusions with adrenaline or adrenaline and phentolamine before and during the last 30 min of the clamp. Dietary intervention induced a body weight reduction and an improved insulin sensitivity. DGC progressively decreased during the clamp, and this decrease was similar during the different phases of the diet. The adrenaline-induced increase in DGC was higher at VLCD and LCD compared with baseline condition and returned to prediet levels at WM. In the probe with adrenaline and phentolamine, the increase in DGC was higher than that in the adrenaline probe at baseline and WM, but it was not different at VLCD and LCD. The results suggest that the responsiveness of SCAT to adrenaline-stimulated lipolysis increases during the calorie-restricted phases due to a reduction of the α2-adrenoceptor-mediated antilipolytic action of adrenaline. At WM, adrenaline-stimulated lipolysis returned to the prediet levels. Furthermore, no direct relationship between insulin sensitivity and the diet-induced changes in the regulation of lipolysis was found.

Early development of lipogenesis in genetically obese (ob/ob) mice

1980 ◽  
Vol 239 (4) ◽  
pp. E265-E265 ◽  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Subcutaneous Adipose Tissue ◽  
Plasma Insulin ◽  
Metabolic Abnormalities ◽  
Hepatic Lipogenesis ◽  
Plasma Insulin Concentration ◽  
Subcutaneous Adipose ◽  
Old Mice

This study was designed to sequence the earliest metabolic abnormalities associated with the development of obesity in the obese hyperglycemic mouse (C57BL/6J ob/ob). In situ lipogenesis was measured with 3H2O in fetuses at day 19 of gestation and in 5-, 10-, 15-, and 35-day-old mice. Preobese 15-day-old animals were identified on the basis of rectal hypothermia. The earliest increased accumulation of fatty acids was observed in the carcass of 15-day-old preobese animals (ob/ob) compared to their lean littermates (+/?) and known lean controls (+/+). The increased carcass lipogenesis in these animals was accompanied by an increase in plasma insulin concentration. Weaned 35-day-old obese animals showed a significant increase in hepatic and subcutaneous adipose tissue lipogenesis, plasma insulin, and glucose values when compared to their littermates (+/?). The results indicate that increased carcass lipogenesis, hyperinsulinemia, and hypothermia appear between days 10 and 15 and that these abnormalities precede the hyperglycemia and increased hepatic lipogenesis observed in the mature ob/ob mice.

Microdialysis of adipose tissue and blood for in vivo lipolysis studies

1988 ◽  
Vol 255 (5) ◽  
pp. E737-E742 ◽  
Author(s):  
P. Arner ◽  
J. Bolinder ◽  
A. Eliasson ◽  
A. Lundin ◽  
U. Ungerstedt
Keyword(s):  
Adipose Tissue ◽  
Subcutaneous Adipose Tissue ◽  
Venous Blood ◽  
Marked Rise ◽  
Glycerol Level ◽  
Lipolytic Effect ◽  
Subcutaneous Adipose ◽  
Dose Dependent ◽  
Intact Rats

Glycerol levels (lipolysis index) were continuously monitored in intact rats using simultaneous microdialysis of venous blood and subcutaneous adipose tissue. Dialysis probes (0.5 X 4 mm) were implanted and perfused using a microinjection pump. The basal glycerol levels in perfusates of blood and adipose tissue were stable. Intravenous isoproterenol (isoprenaline) increased the glycerol levels in a similar fashion in blood perfusate as compared with plasma and the dialysate of two different adipose tissue probes implanted in the same animal. Isoproterenol included in the adipose tissue dialysis solvent increased the glycerol level in adipose tissue perfusate but not in the blood perfusate; this indicates a local lipolytic effect of catecholamines. Increases in intravenous doses of isoproterenol caused a transient and marked dose-dependent elevation of glycerol in the adipose tissue perfusate and a gradual but less marked rise of glycerol in blood perfusate. This indicates that glycerol kinetics in blood and adipose tissue differ after catecholamine stimulation. In conclusion, microdialysis of blood and subcutaneous adipose tissue offers new and unique possibilities for in vivo lipolysis studies in intact animals.

Regulation of blood flow in adipose tissue: involvement of the cholinergic system

2015 ◽  
Vol 309 (1) ◽  
pp. E55-E62 ◽  
Author(s):  
Richard Sotorník ◽  
Jean-Patrice Baillargeon ◽  
Maude Gagnon-Auger ◽  
Julie Ménard ◽  
Pascal Brassard ◽  
...  
Keyword(s):  
Blood Flow ◽  
Adipose Tissue ◽  
Cholinergic System ◽  
Control Site ◽  
Healthy Individuals ◽  
Vasoactive Agents ◽  
Before And After ◽  
Subcutaneous Adipose

Acetylcholine (Ach) has vasodilatory actions. However, data are conflicting about the role of Ach in regulating blood flow in subcutaneous adipose tissue (ATBF). This may be related to inaccurate ATBF recording or to the responder/nonresponder (R/NR) phenomenon. We showed previously that healthy individuals are R (ATBF increases postprandially by >50% of baseline BF) or NR (ATBF increases ≤50% postprandially). Our objective was to assess the role of the cholinergic system on ATBF in R and NR subjects. ATBF was manipulated by in situ microinfusion of vasoactive agents (VA) in AT and monitored by the 133Xenon washout technique (both recognized methods) at the VA site and at the control site. We tested incrementally increasing doses of Ach (10−5, 10−3, and 10−1 mol/l; n = 15) and Ach receptor antagonists (Ra) before and after oral administration of 75-g glucose using atropine (muscarinic Ra; 10−4 mol/l, n = 13; 10−5 mol/l, n = 22) and mecamylamine (nicotinic Ra; 10−3 mol/l, n = 15; 10−4 mol/l, n = 10). Compared with baseline [2.41 (1.36–2.83) ml·100 g−1·min−1], Ach increased ATBF dose dependently [3.32 (2.80–5.09), 6.46 (4.36–9.51), and 10.31 (7.98–11.52), P < 0.0001], with no difference between R and NR. Compared with control side, atropine (both concentrations) had no effect on fasting ATBF; only atropine 10−4 mol/l decreased post-glucose ATBF [iAUC: 1.25 (0.32–2.91) vs. 1.98 (0.64–2.94); P = 0.04]. This effect was further apparent in R. Mecamylamine had no impact on fasting and postglucose ATBF in R and NR. Our results suggest that the cholinergic system is implicated in ATBF regulation, although it has no role in the blunting of ATBF response in NR.

Sign in / Sign up

Export Citation Format

Share Document