scholarly journals Adiponectin Inhibits Spontaneous and Catecholamine-Induced Lipolysis in Human Adipocytes of Non-Obese Subjects Through AMPK-Dependent Mechanisms

2011 ◽  
pp. 139-148 ◽  
Author(s):  
Z. WEDELLOVÁ ◽  
J. DIETRICH ◽  
M. ŠIKLOVÁ-VÍTKOVÁ ◽  
K. KOLOŠTOVÁ ◽  
M. KOVÁČIKOVÁ ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Acid Metabolism ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Glycerol Concentration ◽  
Human Adipocytes ◽  
Compound C ◽  
Obese Subjects ◽  
Surgical Operations

Adiponectin is an adipokine increasing glucose and fatty acid metabolism and improving insulin sensitivity. The aim of this study was to investigate the role of adiponectin in the regulation of adipocyte lipolysis. Human adipocytes isolated from biopsies obtained during surgical operations from 16 non-obese and 17 obese subjects were incubated with 1) human adiponectin (20 µg/ml) or 2) 0.5 mM AICAR – activator of AMPK (adenosine monophosphate activated protein kinase). Following these incubations, isoprenaline was added (10-6 M) to investigate the influence of adiponectin and AICAR on catecholamine-induced lipolysis. Glycerol concentration was measured as lipolysis marker. We observed that adiponectin suppressed spontaneous lipolysis by 21 % and isoprenaline-induced lipolysis by 14 % in non-obese subjects. These effects were not detectable in obese individuals, but statistically significant differences in the effect of adiponectin between obese and non-obese were not revealed by two way ANOVA test. The inhibitory effect of AICAR and adiponectin on lipolysis was reversed by Compound C. Our results suggest, that adiponectin in physiological concentrations inhibits spontaneous as well as catecholamine-induced lipolysis. This effect might be lower in obese individuals and this regulation seems to involve AMPK.

Role of the AMP-activated protein kinase in regulating fatty acid metabolism during exerciseThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 34 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Gregory R. Steinberg
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Moderate Intensity ◽  
Amp Activated Protein Kinase

During moderate-intensity exercise, fatty acids are the predominant substrate for working skeletal muscle. The release of fatty acids from adipose tissue stores, combined with the ability of skeletal muscle to actively fine tune the gradient between fatty acid and carbohydrate metabolism, depending on substrate availability and energetic demands, requires a coordinated system of metabolic control. Over the past decade, since the discovery that AMP-activated protein kinase (AMPK) was increased in accordance with exercise intensity, there has been significant interest in the proposed role of this ancient stress-sensing kinase as a critical integrative switch controlling metabolic responses during exercise. In this review, studies examining the role of AMPK as a regulator of fatty acid metabolism in both adipose tissue and skeletal muscle during exercise will be discussed. Exercise induces activation of AMPK in adipocytes and regulates triglyceride hydrolysis and esterfication through phosphorylation of hormone sensitive lipase (HSL) and glycerol-3-phosphate acyl-transferase, respectively. In skeletal muscle, exercise-induced activation of AMPK is associated with increases in fatty acid uptake, phosphorylation of HSL, and increased fatty acid oxidation, which is thought to occur via the acetyl-CoA carboxylase-malony-CoA-CPT-1 signalling axis. Despite the importance of AMPK in regulating fatty acid metabolism under resting conditions, recent evidence from transgenic models of AMPK deficiency suggest that alternative signalling pathways may also be important for the control of fatty acid metabolism during exercise.

Regulation of free fatty acid metabolism by insulin in humans: role of lipolysis and reesterification

2006 ◽  
Vol 263 (6) ◽  
pp. E1063-E1069 ◽  
Author(s):  
P. J. Campbell ◽  
M. G. Carlson ◽  
J. O. Hill ◽  
N. Nurjhan
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Acid Metabolism ◽  
Insulin Dose ◽  
Healthy Humans ◽  
Constant Rate ◽  
Free Fatty Acid Metabolism ◽  
Plasma Ffa ◽  
Maximal Suppression

The regulation of lipolysis, free fatty acid appearance into plasma (FFA R(a)), an FFA reesterification and oxidation were examined in seven healthy humans infused intravenously with insulin at rates of 4, 8, 25, and 400 mU.m-2.min-1. Glycerol and FFA R(a) were determined by isotope dilution methods, and FFA oxidation was calculated by indirect calorimetry or by measurement of expired 14CO2 from infused [1-14C]palmitate. These measurements were used to calculate total FFA reesterification, primary FFA reesterification occurring within the adipocyte, and secondary reesterification of circulating FFA molecules. Lipolysis, FFA R(a), and secondary FFA reesterification were exquisitely insulin sensitive [the insulin concentrations that produced half-maximal suppression (EC50), 106 +/- 26, 91 +/- 20 vs. 80 +/- 16 pM, P = not significant] in contrast to insulin suppression of FFA oxidation (EC50, 324 +/- 60, all P < 0.01). The absolute rate of primary FFA reesterification was not affected by the increase in insulin concentration, but the proportion of FFA molecules undergoing primary reesterification doubled over the physiological portion of the insulin dose-response curve (from 0.23 +/- 0.06 to 0.44 +/- 0.07, P < 0.05). This served to magnify insulin suppression of FFA R(a) twofold. In conclusion, insulin regulates FFA R(a) by inhibition of lipolysis while maintaining a constant rate of primary FFA reesterification.

scholarly journals The Role of Fatty Acid Metabolism and Apolipoproteins in Ths-Induced Hepatic Steatosis in Mice

2017 ◽  
Vol 07 (04) ◽  
Author(s):  
Cristina Flores ◽  
Neema Adhami ◽  
Manuela Martins Green
Keyword(s):  
Fatty Acid ◽  
Hepatic Steatosis ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism

scholarly journals Increased Excretion of C4-Carnitine Species after a Therapeutic Acetylsalicylic Acid Dose: Evidence for an Inhibitory Effect on Short-Chain Fatty Acid Metabolism

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Catharina M. C. Mels ◽  
Peet Jansen van Rensburg ◽  
Francois H. van der Westhuizen ◽  
Pieter J. Pretorius ◽  
Elardus Erasmus
Keyword(s):  
Fatty Acid ◽  
Acetylsalicylic Acid ◽  
Fatty Acid Metabolism ◽  
Short Chain Fatty Acid ◽  
Acid Metabolism ◽  
Human Subjects ◽  
Inhibitory Effect ◽  
Chain Fatty Acid ◽  
Short Chain

Acetylsalicylic acid and/or its metabolites are implicated to have various effects on metabolism and, especially, on mitochondrial function. These effects include both inhibitory and stimulatory effects. We investigated the effect of both combined and separate oral acetylsalicylic acid and acetaminophen administration at therapeutic doses on the urinary metabolite profile of human subjects. In this paper, we provided in vivo evidence, in human subjects, of a statistically significant increase in isobutyrylcarnitine after the administration of a therapeutic dose of acetylsalicylic acid. We, therefore, propose an inhibitory effect of acetylsalicylic acid on the short-chain fatty acid metabolism, possibly at the level of isobutyryl-CoA dehydrogenase.

The Role of Fatty Acid Metabolism and Apolipoproteins in Ths-Induced Hepatic Steatosis in Mice

2017 ◽  
Vol 07 (04) ◽  
Author(s):  
Cristina Flores ◽  
Neema Adhami ◽  
Manuela Martins Green
Keyword(s):  
Fatty Acid ◽  
Hepatic Steatosis ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism

scholarly journals Role of PKC and AMPK in hypertonicity-stimulated water reabsorption in rat inner medullary collecting ducts

2019 ◽  
Vol 316 (2) ◽  
pp. F253-F262 ◽  
Author(s):  
Josephine K. Liwang ◽  
Joseph A. Ruiz ◽  
Lauren M. LaRocque ◽  
Fitra Rianto ◽  
Fuying Ma ◽  
...  
Keyword(s):  
Water Permeability ◽  
Collecting Duct ◽  
Adenosine Monophosphate ◽  
Osmotic Water Permeability ◽  
Water Reabsorption ◽  
Compound C ◽  
Ampk Phosphorylation ◽  
Osmotic Water ◽  
Medullary Collecting Duct

Hypertonicity increases water permeability, independently of vasopressin, in the inner medullary collecting duct (IMCD) by increasing aquaporin-2 (AQP2) membrane accumulation. We investigated whether protein kinase C (PKC) and adenosine monophosphate kinase (AMPK) are involved in hypertonicity-regulated water permeability. Increasing perfusate osmolality from 150 to 290 mosmol/kgH2O and bath osmolality from 290 to 430 mosmol/kgH2O significantly stimulated osmotic water permeability. The PKC inhibitors chelerythrine (10 µM) and rottlerin (50 µM) significantly reversed the increase in osmotic water permeability stimulated by hypertonicity in perfused rat terminal IMCDs. Chelerythrine significantly increased phosphorylation of AQP2 at S261 but not at S256. Previous studies show that AMPK is stimulated by osmotic stress. We tested AMPK phosphorylation under hypertonic conditions. Hypertonicity significantly increased AMPK phosphorylation in inner medullary tissues. Blockade of AMPK with Compound C decreased hypertonicity-stimulated water permeability but did not alter phosphorylation of AQP2 at S256 and S261. AICAR, an AMPK stimulator, caused a transient increase in osmotic water permeability and increased phosphorylation of AQP2 at S256. When inner medullary tissue was treated with the PKC activator phorbol dibutyrate (PDBu), the AMPK activator metformin, or both, AQP2 phosphorylation at S261 was decreased with PDBu or metformin alone, but there was no additive effect on phosphorylation with PDBu and metformin together. In conclusion, hypertonicity regulates water reabsorption by activating PKC. Hypertonicity-stimulated water reabsorption by PKC may be related to the decrease in endocytosis of AQP2. AMPK activation promotes water reabsorption, but the mechanism remains to be determined. PKC and AMPK do not appear to act synergistically to regulate water reabsorption.

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