Acute exposure to long-chain fatty acids impairs {alpha}2-adrenergic receptor-mediated antilipolysis in human adipose tissue.
The acute in vitro and in vivo effects of long-chain fatty acids (LCFAs) on the regulation of adrenergic lipolysis were investigated in human adipose tissue. The effect of a 2 h incubation, without or with LCFA (200 mumol/l), on basal and hormonally induced lipolysis was tested in vitro on isolated fat cells. The lipolytic response to epinephrine was enhanced by suppression of the antilipolytic alpha(2)-adrenergic effect. Then, healthy lean and obese male subjects performed a 45 min exercise bout at 50% of their heart rate reserve either after an overnight fast or 3 h after a high-fat meal (HFM: 95% fat, 5% carbohydrates). Subcutaneous adipose tissue lipolysis was measured by microdialysis in the presence or absence of an alpha-antagonist (phentolamine). In vivo, a HFM increased plasma levels of nonesterified fatty acids in lean and obese subjects. In both groups, the HFM did not alter hormonal responses to exercise. Under fasting conditions, the alpha(2)-adrenergic antilipolytic effect was more pronounced in obese than in lean subjects. The HFM totally suppressed the alpha(2)-adrenergic antilipolytic effect in lean and obese subjects during exercise. LCFAs per se, in vitro as well as in vivo, suppress alpha(2)-adrenergic-mediated antilipolysis in adipose tissue. LCFA-mediated suppression of antilipolytic pathways represents another mechanism whereby a high fat content in the diet might increase adipose tissue lipolysis.
Polak
Jan
J
Franco-Czech Laboratory for Clinical Research on Obesity, French Institute of Health and Medical Research (Institut National de la Santé et de la Recherche Médicale U858), Charles University in Prague, Prague, Czech Republic.
Moro
Cédric
C
Bessière
David
D
Hejnova
Jindra
J
Marquès
Marie A
MA
Bajzova
Magda
M
Lafontan
Max
M
Crampes
Francois
F
Berlan
Michel
M
Stich
Vladimir
V
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D004041:Dietary Fats; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D005502:Food; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008066:Lipolysis; D008297:Male; D017551:Microdialysis; D008875:Middle Aged; D009765:Obesity; D010646:Phentolamine / Q000494:pharmacology; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism*
D004041:Dietary Fats; D005227:Fatty Acids; D007328:Insulin; D018341:Receptors, Adrenergic, alpha-2; D010646:Phentolamine