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Effect of beta-adrenergic stimulation on whole-body and abdominal subcutaneous adipose tissue lipolysis in lean and obese men.

Jocken JW, Goossens GH, van Hees AM, Frayn KN, van Baak M, Stegen J, Pakbiers MT, Saris WH, Blaak EE - Diabetologia (2007)

Bottom Line: We hypothesised that the beta-adrenergically mediated effect on lipolysis in abdominal SAT is also impaired in vivo in obese humans.However, their fasting lipolysis was blunted [glycerol rate of appearance: 7.3+/-0.6 vs 13.1+/-0.9 micromol (kg fat mass)(-1) min(-1), p<0.01], as was the beta-adrenergically mediated lipolytic response per unit SAT [Delta total glycerol release: 140+/-71 vs 394+/-112 nmol (100 g tissue)(-1) min(-1), p<0.05] compared with lean participants.Net triacylglycerol flux tended to increase in obese compared with lean participants during beta-adrenergic stimulation [Delta net triacylglycerol flux: 75+/-32 vs 16+/-11 nmol (100 g tissue)(-1) min(-1), p=0.06].

View Article: PubMed Central - PubMed

Affiliation: Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, and Department of Nuclear Medicine, University Hospital Maastricht, Maastricht, The Netherlands. J.Jocken@HB.Unimaas.nl

ABSTRACT

Aims/hypothesis: Obesity is characterised by increased triacylglycerol storage in adipose tissue. There is in vitro evidence for a blunted beta-adrenergically mediated lipolytic response in abdominal subcutaneous adipose tissue (SAT) of obese individuals and evidence for this at the whole-body level in vivo. We hypothesised that the beta-adrenergically mediated effect on lipolysis in abdominal SAT is also impaired in vivo in obese humans.

Methods: We investigated whole-body and abdominal SAT glycerol metabolism in vivo during 3 h and 6 h [2H5]glycerol infusions. Arterio-venous concentration differences were measured in 13 lean and ten obese men after an overnight fast and during intravenous infusion of the non-selective beta-adrenergic agonist isoprenaline [20 ng (kg fat free mass)(-1) min(-1)].

Results: Lean and obese participants showed comparable fasting glycerol uptake by SAT (9.7+/-3.4 vs 9.3+/-2.5% of total release, p=0.92). Furthermore, obese participants showed an increased whole-body beta-adrenergically mediated lipolytic response versus lean participants. However, their fasting lipolysis was blunted [glycerol rate of appearance: 7.3+/-0.6 vs 13.1+/-0.9 micromol (kg fat mass)(-1) min(-1), p<0.01], as was the beta-adrenergically mediated lipolytic response per unit SAT [Delta total glycerol release: 140+/-71 vs 394+/-112 nmol (100 g tissue)(-1) min(-1), p<0.05] compared with lean participants. Net triacylglycerol flux tended to increase in obese compared with lean participants during beta-adrenergic stimulation [Delta net triacylglycerol flux: 75+/-32 vs 16+/-11 nmol (100 g tissue)(-1) min(-1), p=0.06].

Conclusions/interpretation: We demonstrated in vivo that beta-adrenergically mediated lipolytic response is impaired systematically and in abdominal SAT of obese versus lean men. This may be important in the development or maintenance of increased triacylglycerol stores and obesity.

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Total glycerol uptake (a) and release (b) across abdominal SAT after an overnight fast (black bars) and during beta-adrenergic stimulation (white bars) in obese vs lean participants during 3 h [2H5]glycerol infusion. Values are mean ± SEM. *p < 0.05 for change (Δ) from baseline obese vs lean
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Fig2: Total glycerol uptake (a) and release (b) across abdominal SAT after an overnight fast (black bars) and during beta-adrenergic stimulation (white bars) in obese vs lean participants during 3 h [2H5]glycerol infusion. Values are mean ± SEM. *p < 0.05 for change (Δ) from baseline obese vs lean

Mentions: Glycerol uptake by abdominal SAT was observed in lean and obese participants after an overnight fast (Fig. 2a). Fractional extraction of [2H5]glycerol from the circulation (lean vs obese, 16.6 ± 4.5 vs 13.9 ± 6.7%) and total glycerol uptake expressed relative to total glycerol release were very small (lean vs obese, 9.7 ± 3.4 vs 9.3 ± 2.5% of total release) with no significant difference between lean and obese participants (p = 0.74 and p = 0.92, respectively). Adipose tissue total glycerol uptake increased during beta-adrenergic stimulation in lean and obese participants, but this increase was not significantly different between groups [Δ total glycerol uptake obese vs lean, 4 ± 9 vs 21 ± 5 nmol (100 g tissue)−1 min−1, p = 0.15] (Fig. 2a). The increased total glycerol uptake during beta-adrenergic stimulation appeared to be partly explained by the increase in ATBF (r = 0.633, p < 0.05).Fig. 2


Effect of beta-adrenergic stimulation on whole-body and abdominal subcutaneous adipose tissue lipolysis in lean and obese men.

Jocken JW, Goossens GH, van Hees AM, Frayn KN, van Baak M, Stegen J, Pakbiers MT, Saris WH, Blaak EE - Diabetologia (2007)

Total glycerol uptake (a) and release (b) across abdominal SAT after an overnight fast (black bars) and during beta-adrenergic stimulation (white bars) in obese vs lean participants during 3 h [2H5]glycerol infusion. Values are mean ± SEM. *p < 0.05 for change (Δ) from baseline obese vs lean
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2170457&req=5

Fig2: Total glycerol uptake (a) and release (b) across abdominal SAT after an overnight fast (black bars) and during beta-adrenergic stimulation (white bars) in obese vs lean participants during 3 h [2H5]glycerol infusion. Values are mean ± SEM. *p < 0.05 for change (Δ) from baseline obese vs lean
Mentions: Glycerol uptake by abdominal SAT was observed in lean and obese participants after an overnight fast (Fig. 2a). Fractional extraction of [2H5]glycerol from the circulation (lean vs obese, 16.6 ± 4.5 vs 13.9 ± 6.7%) and total glycerol uptake expressed relative to total glycerol release were very small (lean vs obese, 9.7 ± 3.4 vs 9.3 ± 2.5% of total release) with no significant difference between lean and obese participants (p = 0.74 and p = 0.92, respectively). Adipose tissue total glycerol uptake increased during beta-adrenergic stimulation in lean and obese participants, but this increase was not significantly different between groups [Δ total glycerol uptake obese vs lean, 4 ± 9 vs 21 ± 5 nmol (100 g tissue)−1 min−1, p = 0.15] (Fig. 2a). The increased total glycerol uptake during beta-adrenergic stimulation appeared to be partly explained by the increase in ATBF (r = 0.633, p < 0.05).Fig. 2

Bottom Line: We hypothesised that the beta-adrenergically mediated effect on lipolysis in abdominal SAT is also impaired in vivo in obese humans.However, their fasting lipolysis was blunted [glycerol rate of appearance: 7.3+/-0.6 vs 13.1+/-0.9 micromol (kg fat mass)(-1) min(-1), p<0.01], as was the beta-adrenergically mediated lipolytic response per unit SAT [Delta total glycerol release: 140+/-71 vs 394+/-112 nmol (100 g tissue)(-1) min(-1), p<0.05] compared with lean participants.Net triacylglycerol flux tended to increase in obese compared with lean participants during beta-adrenergic stimulation [Delta net triacylglycerol flux: 75+/-32 vs 16+/-11 nmol (100 g tissue)(-1) min(-1), p=0.06].

View Article: PubMed Central - PubMed

Affiliation: Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, and Department of Nuclear Medicine, University Hospital Maastricht, Maastricht, The Netherlands. J.Jocken@HB.Unimaas.nl

ABSTRACT

Aims/hypothesis: Obesity is characterised by increased triacylglycerol storage in adipose tissue. There is in vitro evidence for a blunted beta-adrenergically mediated lipolytic response in abdominal subcutaneous adipose tissue (SAT) of obese individuals and evidence for this at the whole-body level in vivo. We hypothesised that the beta-adrenergically mediated effect on lipolysis in abdominal SAT is also impaired in vivo in obese humans.

Methods: We investigated whole-body and abdominal SAT glycerol metabolism in vivo during 3 h and 6 h [2H5]glycerol infusions. Arterio-venous concentration differences were measured in 13 lean and ten obese men after an overnight fast and during intravenous infusion of the non-selective beta-adrenergic agonist isoprenaline [20 ng (kg fat free mass)(-1) min(-1)].

Results: Lean and obese participants showed comparable fasting glycerol uptake by SAT (9.7+/-3.4 vs 9.3+/-2.5% of total release, p=0.92). Furthermore, obese participants showed an increased whole-body beta-adrenergically mediated lipolytic response versus lean participants. However, their fasting lipolysis was blunted [glycerol rate of appearance: 7.3+/-0.6 vs 13.1+/-0.9 micromol (kg fat mass)(-1) min(-1), p<0.01], as was the beta-adrenergically mediated lipolytic response per unit SAT [Delta total glycerol release: 140+/-71 vs 394+/-112 nmol (100 g tissue)(-1) min(-1), p<0.05] compared with lean participants. Net triacylglycerol flux tended to increase in obese compared with lean participants during beta-adrenergic stimulation [Delta net triacylglycerol flux: 75+/-32 vs 16+/-11 nmol (100 g tissue)(-1) min(-1), p=0.06].

Conclusions/interpretation: We demonstrated in vivo that beta-adrenergically mediated lipolytic response is impaired systematically and in abdominal SAT of obese versus lean men. This may be important in the development or maintenance of increased triacylglycerol stores and obesity.

Show MeSH
Related in: MedlinePlus