Exercise training decreases in vitro stimulated lipolysis in a visceral (mesenteric) but not in the retroperitoneal fat depot of high-fat-fed rats

Chapados, Natalie Ann; Collin, Pascal; Imbeault, Pascal; Corriveau, Pierre; Lavoie, Jean‐Marc

doi:10.1017/s0007114508921735

Cited by 22 publications

(17 citation statements)

References 32 publications

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“…In this study, Epid and SC Ing fat masses and adipocyte area were indeed significantly lower in Ex than Sed rats. Conversely, previous studies in isolated adipocytes from rats 30 and humans 11 reporting an increase in lipolysis in response to chronic endurance training did not show any significant alteration in body weight or adiposity with endurance training, which could be the reason for the apparent discrepant findings from this and other studies in isolated rat adipocytes 16 in which adiposity is reduced with chronic endurance training.…”

Section: Discussioncontrasting

confidence: 99%

“…However, at odds with these findings are the results of studies measuring catecholamine-stimulated glycerol release in isolated adipocytes from humans [7][8][9][10][11] and rats, [12][13][14][15] which report increased WAT lipolysis after a period of endurance training. Additional studies have reported lipolysis to be either reduced in isolated rat adipocytes 16 or unaltered when assessed in situ by the microdialysis technique in human WAT 17 following a period of endurance training. It is often difficult to reconcile apparent discrepant findings regarding the effects of chronic endurance training on WAT lipolysis when large methodological variability exists among studies.…”

Section: Introductionmentioning

confidence: 99%

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Lipolysis, lipogenesis, and adiposity are reduced while fatty acid oxidation is increased in visceral and subcutaneous adipocytes of endurance-trained rats

et al. 2014

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(2015) Lipolysis, lipogenesis, and adiposity are reduced while fatty acid oxidation is increased in visceral and subcutaneous adipocytes of endurance-trained rats, Adipocyte, 4:1, 22-31, DOI: 10.4161/21623945.2014 This study examined the alterations in triglyceride (TG) breakdown and storage in subcutaneous inguinal (SC Ing) and epididymal (Epid) fat depots following chronic endurance training. Male Wistar rats were either kept sedentary (Sed) or subjected to endurance training (Ex) at 70-85% peak VO 2 for 6 weeks. At weeks 0, 3, and 6 blood was collected at rest and immediately after a bout of submaximal exercise of similar relative intensity to assess whole-body lipolysis. At week 6, adipocytes were isolated from Epid and SC Ing fat pads for the determination of lipolysis under basal or isoproterenol-and forskolin-stimulated conditions, basal and insulin-stimulated glucose incorporation into lipids, and fatty acid oxidation (FAO). Body weight, fat pad mass, and insulin were reduced by endurance training. Also, circulating non-esterified fatty acids (NEFAs) were 33% lower in Ex than Sed rats when exercising at the same relative intensity. This coincided with reduced isoproterenol-stimulated lipolysis in the Epid (27%) and SC Ing (25%) adipocytes in Ex rats. Similarly, forskolin-stimulated lipolysis was reduced in Epid (51%) and SC Ing (49%) adipocytes from Ex rats. Insulinstimulated glucose incorporation into lipids in adipocytes from both fat depots from Ex rats was also lower (»43%) than Sed controls. Conversely, FAO was increased in Epid (1.71-fold) and SC Ing (1.82-fold) adipocytes of Ex rats. In conclusion, chronic endurance exercise reduced lipolysis and lipogenesis while increasing FAO in Epid and SC Ing adipocytes. These are compatible with an energy-sparing adaptive response to reduced adiposity under chronic endurance training conditions.

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Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lipolysis, lipogenesis, and adiposity are reduced while fatty acid oxidation is increased in visceral and subcutaneous adipocytes of endurance-trained rats

et al. 2014

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“…In addition, voluntary exercise in the OVX mice did not prevent the decrease in perilipin protein content in the visceral adipose tissue, while 17b-estradiol supplementation completely attenuated the decrease. Previous research indicates that voluntary exercise does not change perilipin protein content in the mesenteric fat pad [Chapados et al, 2008]; however, 17b-estradiol supplementation does prevent the loss of perilipin [D'Eon et al, 2005]. Following the breakdown of TAG to DAG by ATGL, HSL continues the process of lipolysis, breaking DAG to MAG.…”

Section: Discussionmentioning

confidence: 99%

17β‐estradiol supplementation attenuates ovariectomy‐induced increases in ATGL signaling and reduced perilipin expression in visceral adipose tissue

Wohlers

Spangenburg

2010

J of Cellular Biochemistry

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Adipocytes from post-menopausal females have higher basal lipolytic rates than pre-menopausal females, which contributes to increased risk of developing dyslipidemia following menopause. The purpose of this study was to delineate cellular mechanisms affecting adipose tissue function in the ovariectomized (OVX) mouse and also determine if physical activity or estrogen supplementation alter any detected changes. Female C57/Bl6 mice were placed into SHAM, OVX sedentary (OVX), OVX exercise (OVX-Ex), and OVX sedentary + 17beta-estradiol (OVX + E(2)) groups. Visceral fat mass, glycerol, and NEFA levels were significantly higher in OVX mice compared to SHAM animals, but were not elevated in the E(2)-treated animals. Voluntary running failed to change circulating levels of glycerol or NEFA in OVX mice, but did partially attenuate the increase in visceral fat mass. Adipose triglyceride lipase (ATGL) protein content was significantly elevated in visceral fat from OVX and OVX-Ex groups compared to SHAM, while ATGL-CGI-58 interaction was significantly higher in OVX than SHAM and OVX + E(2) mice. No significant differences in HSL phosphorylation were detected between groups, however, ERK1/2 phosphorylation was significantly elevated in the OVX mice. To determine if ERK1/2 function was critical for the increased glycerol levels, visceral fat was treated with MEK inhibitor PD98059, with no differences in glycerol release detected. Perilipin protein content was decreased significantly in OVX and OVX-Ex mice compared to SHAM. Thus, these data suggest that increased ATGL signaling and reduced perilipin protein content may contribute to increased NEFA and glycerol levels in OVX mice, which are attenuated with E(2) treatment, but not by exercise.

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“…In other respects, it has been reported that exercise training results in an improvement in hepatic steatosis in humans [14] and in an attenuation [15] , reversal [16] , or complete suppression [17] in rats. Mechanisms by which exercise training may reduce hepatic steatosis include a decrease in nonesterifi ed fatty acid (NEFA) mobilization from mesenteric adipose tissue [18] , an increased hepatic fatty acid oxidation [15] , and a reduced lipogenesis [15,19] in rats. In human, hepatic VLDL-triglyceride (VLDL-TG) secretion rate has been recently Abstract &…”

mentioning

confidence: 99%

Effects of Exercise Training on Hepatic Microsomal Triglyceride Transfer Protein Content in Rats

Chapados

Seelaender²,

Lévy³

et al. 2008

Horm Metab Res

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Microsomal triglyceride transfer protein (MTP) is a protein that exerts a central regulatory role in very-low-density lipoprotein (VLDL) assembly and secretion. The purpose of the study was to investigate the effects of an exercise-training program on hepatic content of MTP and its relation to hepatic VLDL-triglyceride (VLDL-TG) production in response to lipid infusion. Female rats either fed a standard (SD) or an obesity-induced high-fat (HF; 43% as energy) diet for 8 weeks were subdivided into sedentary (Sed) and trained (Tr) groups. Exercise training consisted of continuous running on a motor-driven rodent treadmill 5 times/week for 8 weeks. At the end of this period, all rats in the fasted state were intravenously infused with a 20% solution of Intralipid for 3 h followed by an injection of Triton WR1339 to block lipoprotein lipase. An additional control group consisting of Sed rats fed the SD diet was infused with saline (0.9% NaCl). Plasma TG accumulation was thereafter measured during 90 min to estimate VLDL-TG production. Under HF diet, hepatic MTP content and plasma TG accumulation after Triton blockade (thus reflecting VLDL-TG synthesis and secretion) were not changed in Sed rats, whereas liver TG content was highly increased (approximately 90%; p<0.01). On the other hand, training reduced liver MTP protein content in both SD (-18%) and HF (-23%) fed rats (p<0.05). Plasma VLDL-TG accumulation was also lower (p<0.05) in Tr than in Sed rats fed the HF diet. This effect was not observed in SD fed rats. Furthermore, the exercise training-induced decrease in VLDL-TG production in HF rats was associated with a decrease in liver TG levels. It is concluded that in addition to a reduction in liver TG content, exercise training reduces VLDL synthesis and/or secretion in HF fed rats probably via MTP regulation.

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Exercise training decreases in vitro stimulated lipolysis in a visceral (mesenteric) but not in the retroperitoneal fat depot of high-fat-fed rats

Cited by 22 publications

References 32 publications

Lipolysis, lipogenesis, and adiposity are reduced while fatty acid oxidation is increased in visceral and subcutaneous adipocytes of endurance-trained rats

Lipolysis, lipogenesis, and adiposity are reduced while fatty acid oxidation is increased in visceral and subcutaneous adipocytes of endurance-trained rats

17β‐estradiol supplementation attenuates ovariectomy‐induced increases in ATGL signaling and reduced perilipin expression in visceral adipose tissue

Effects of Exercise Training on Hepatic Microsomal Triglyceride Transfer Protein Content in Rats

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