Effect of Weight Reduction on in Vitro Adipose Tissue Lipolysis and Cellularity in Obese Adolescents and Adults

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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Regulation of lipolysis by somatotropin: functional alteration of adrenergic and adenosine signaling in bovine adipose tissue

Journal of Endocrinology ◽

10.1677/joe.0.1520465 ◽

1997 ◽

Vol 152 (3) ◽

pp. 465-475 ◽

Cited By ~ 18

Author(s):

K L Houseknecht ◽

D E Bauman

Keyword(s):

Adipose Tissue ◽

Signaling Proteins ◽

Heterotrimeric G Proteins ◽

Adrenergic Stimulation ◽

Cellular Mechanisms ◽

Lactating Cows ◽

Adipose Tissue Lipolysis ◽

Stimulation Of

To investigate the cellular mechanisms of somatotropin (ST) action on adipose tissue lipolysis, experiments were conducted using adipose tissue taken from lactating cows treated with excipient or ST (40 mg/day). Stimulation of lipolysis in vitro by the effectors isoproterenol with or without adenosine deaminase, dibutyryl cAMP with or without isobutylmethylxanthine, and forskolin was not altered by ST treatment. Conversely, the response to the antilipolytic effector, phenylisopropyladenosine (PIA), was significantly reduced in adipose tissue explants from ST or fasted cows. The different responses to adrenergic-stimulating agents (in vivo) and PIA (in vitro) were not due to differences in the abundance of α, β or γ subunits of the stimulatory (Gs) and inhibitory (Gi) subunits of the heterotrimeric G-proteins which bind to the β-adrenergic and adenosine receptors respectively. However, the functionality of Gi proteins, as assessed by their ability to be ADP-ribosylated by pertussis toxin, was significantly reduced in ST-treated but not fasted cows. These data highlight differential regulation of signaling proteins by ST and fasting, both of which result in enhanced in vivo response to adrenergic stimulation of lipolysis. Journal of Endocrinology (1997) 152, 465–475

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Impact of Branched Chain Amino Acid Supplementation on Adipose Tissue Lipolysis

Current Developments in Nutrition ◽

10.1093/cdn/nzab041_011 ◽

2021 ◽

Vol 5 (Supplement_2) ◽

pp. 496-496

Author(s):

Tabitha Gregory ◽

Chaitra Surugihalli ◽

Vaishna Muralidaran ◽

Marilyn Fisher ◽

Nishanth Sunny

Keyword(s):

Adipose Tissue ◽

Amino Acid Supplementation ◽

Low Fat ◽

Subsequent Increase ◽

Tissue Samples ◽

Peripheral Tissues ◽

Tissue Protein ◽

Adipose Tissue Lipolysis ◽

Branched Chain

Abstract Objectives Branched chain amino acids (BCAAs), Valine, Leucine, and Isoleucine have been shown to impact adipose tissue physiology through regulation of adipocyte differentiation, lipogenesis, and lipolysis. Further, circulating BCAAs are elevated during obesity and insulin resistance, a characteristic attributed to impaired BCAA catabolic networks in adipose tissue and skeletal muscle. The objective of this study was to determine whether the induction of lipolysis in adipose tissue is a characteristic feature prompted by the chronic availability of BCAAs. Methods Mice (C57-BL6N) were kept on low-fat (LF, 10% fat calories; n = 9) and low-fat supplemented with 150% BCAA (LB; n = 10) diets for 34 weeks. Following an overnight fast (∼12–14 hrs), serum and perigonadal adipose (PGA) tissue samples were collected for metabolic analysis. Serum free fatty acids (FFAs) were analyzed and 25 milligrams (mg) of PGA was used for an in vitro lipolysis assay. Lipolysis in the PGA was induced under basal and isoproterenol (ISP, 10 micromolar, μM) stimulated conditions for 2 hours. In a second experiment, PGA tissue explants from normal mice (n = 18) were incubated with two levels of BCAA supplementation (500 μM and 1 millimolar, mM). FFAs in the incubation media were measured as an index of adipose tissue lipolysis. Results Overnight fasting body weights of the LF and LB mice remained similar. However, PGA tissue weights were significantly lower in the LB group (grams ± SEM; LF, 1.34 ± 0.09 vs LB, 0.84 ± 0.11, P = 0.003). LB serum FFAs were elevated (mM FFAs ± SEM; LF 0.73 ± 0.04 vs LB, 0.88 ± 0.04, P = 0.01). Basal lipolysis (mM FFAs/mg tissue protein ± SEM) trended to be higher in the PGA from the LB animals (LF, 1.44 ± 0.18 vs LB, 1.88 ± 0.15, P = 0.08). While ISP significantly induced lipolysis, the stimulated lipolytic rates remained similar between LF and LB groups. When normal PGA explants were challenged with BCAAs, the 1mM BCAA supplemented group tended to show higher fatty acid release (mM FFAs/mg tissue protein ± SEM; 500 μM, 0.89 ± 0.06 vs 1mM, 1.02 ± 0.05, P = 0.09). Conclusions In summary, these results suggest that BCAA mediated increases in adipose tissue lipolysis can contribute to circulating FFA levels. BCAA mediated lipolysis and the subsequent increase in circulating FFAs could indirectly modulate substrate oxidation in peripheral tissues including liver and muscle. Funding Sources NIH RO1

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Acute metabolic effects of adrenergic agents in swine

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1987.252.1.e85 ◽

1987 ◽

Vol 252 (1) ◽

pp. E85-E95 ◽

Cited By ~ 2

Author(s):

H. J. Mersmann

Keyword(s):

Adipose Tissue ◽

Fatty Acid ◽

Free Fatty Acid ◽

Plasma Free Fatty Acid ◽

Metabolic Effects ◽

Adipose Tissue Lipolysis ◽

Beta 2 ◽

Stimulation Of

A pig model in vivo was used to confirm the unique specificity for stimulation of porcine adipose tissue lipolysis by norepinephrine analogues in vitro. Plasma free fatty acid and blood glycerol concentrations were monitored as probable indicators of adipose tissue lipolysis. Plasma glucose and lactate concentrations, blood pressure, and heart rate were monitored also. Norepinephrine analogues were infused intravenously. Several compounds, classified as either beta 1- or beta 2-adrenergic agonists, that stimulated lipolysis in vitro also increased plasma free fatty acid and blood glycerol concentrations in vivo. Tazolol (beta 1) and quinterenol (beta 2) did not stimulate lipolysis in vitro and likewise did not elevate plasma free fatty acid or blood glycerol concentrations in vivo. Clenbuterol and zinterol did not stimulate lipolysis in vitro but elevated plasma free fatty acid concentrations in vivo, implying indirect effects. Isoproterenol stimulation of plasma free fatty acid and blood glycerol concentrations in vivo was antagonized by propranolol, implying the beta-adrenergic nature of the receptors. Infusion of purported beta 1- and beta 2-adrenergic antagonists suggested control of lipolysis in vivo predominantly by beta 1-adrenergic receptors; however, because the results in vitro do not indicate this specificity, differential pharmacodynamics of the antagonists are suggested rather than designation of receptor subtypes. There was no evidence for alpha-adrenergic mediated inhibition of adipose tissue lipolysis in vivo, confirming observations in vitro.

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Effect of an amphetamine derivative on rat adipose tissue lipolysis and glycerol utilization in vitro

Biochemical Pharmacology ◽

10.1016/0006-2952(73)90205-0 ◽

1973 ◽

Vol 22 (23) ◽

pp. 3131-3133 ◽

Cited By ~ 1

Author(s):

Emilio Herrera ◽

Angel Pascual

Keyword(s):

Adipose Tissue ◽

Glycerol Utilization ◽

Adipose Tissue Lipolysis ◽

Rat Adipose Tissue

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The effect of dietary lipids on lipolysis in rat adipose tissue

British Journal Of Nutrition ◽

10.1079/bjn19750031 ◽

1975 ◽

Vol 33 (2) ◽

pp. 291-297 ◽

Cited By ~ 13

Author(s):

P. W. Larking ◽

E. R. Nye

Keyword(s):

Fatty Acids ◽

Adipose Tissue ◽

Dietary Fat ◽

Dietary Lipids ◽

Prostaglandin E ◽

Adipose Tissue Lipolysis ◽

Rat Adipose Tissue ◽

Fasted Rats

1. Rats were fed for 8 weeks on one of five diets differing in the amount of fatty acids 18:1, 18:2 and 18:3. Lipolysis, in vitro, of epididymal fat from fed and fasted rats was measured both basally and in the presence of noradrenaline with and without prostaglandin E12. Lipolysis was markedly influenced by the type of dietary fat. In particular, lipolysis in adipose tissue from rats given diets rich in the fatty acid 18:3 was higher than in the rats given diets containing 18:23. Results showing the effects of fasting on adipose tissue lipolysis are also presented4. The results are discussed in relation to the known effects of unsaturated fats on hyper-plasia and protein synthesis in adipose tissue and on the possible role of prostaglandins.

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A systems biology analysis of lipolysis and fatty acid release from adipocytes in vitro and from adipose tissue in vivo

PLoS ONE ◽

10.1371/journal.pone.0261681 ◽

2021 ◽

Vol 16 (12) ◽

pp. e0261681

Author(s):

William Lövfors ◽

Jona Ekström ◽

Cecilia Jönsson ◽

Peter Strålfors ◽

Gunnar Cedersund ◽

...

Keyword(s):

Fatty Acids ◽

Adipose Tissue ◽

Systemic Circulation ◽

Fatty Acid Release ◽

Adipose Tissue Lipolysis ◽

The Difference ◽

Type 2 Diabetic

Lipolysis and the release of fatty acids to supply energy fuel to other organs, such as between meals, during exercise, and starvation, are fundamental functions of the adipose tissue. The intracellular lipolytic pathway in adipocytes is activated by adrenaline and noradrenaline, and inhibited by insulin. Circulating fatty acids are elevated in type 2 diabetic individuals. The mechanisms behind this elevation are not fully known, and to increase the knowledge a link between the systemic circulation and intracellular lipolysis is key. However, data on lipolysis and knowledge from in vitro systems have not been linked to corresponding in vivo data and knowledge in vivo. Here, we use mathematical modelling to provide such a link. We examine mechanisms of insulin action by combining in vivo and in vitro data into an integrated mathematical model that can explain all data. Furthermore, the model can describe independent data not used for training the model. We show the usefulness of the model by simulating new and more challenging experimental setups in silico, e.g. the extracellular concentration of fatty acids during an insulin clamp, and the difference in such simulations between individuals with and without type 2 diabetes. Our work provides a new platform for model-based analysis of adipose tissue lipolysis, under both non-diabetic and type 2 diabetic conditions.

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