Exercise-induced lipid mobilization in subcutaneous adipose tissue is mainly related to natriuretic peptides in overweight men.
Involvement of sympathetic nervous system and natriuretic peptides in the control of exercise-induced lipid mobilization was compared in overweight and lean men. Lipid mobilization was determined using local microdialysis during exercise. Subjects performed 35-min exercise bouts at 60% of their maximal oxygen consumption under placebo or after oral tertatolol [a beta-adrenergic receptor (AR) antagonist]. Under placebo, exercise increased dialysate glycerol concentration (DGC) in both groups. Phentolamine (alpha-AR antagonist) potentiated exercise-induced lipolysis in overweight but not in lean subjects; the alpha(2)-antilipolytic effect was only functional in overweight men. After tertatolol administration, the DGC increased similarly during exercise no matter which was used probe in both groups. Compared with the control probe under placebo, lipolysis was reduced in lean but not in overweight men treated with the beta-AR blocker. Tertatolol reduced plasma nonesterified fatty acids and insulin concentration in both groups at rest. Under placebo or tertatolol, the exercise-induced changes in plasma nonesterified fatty acids, glycerol, and insulin concentrations were similar in both groups. Exercise promoted a higher increase in catecholamine and ANP plasma levels after tertatolol administration. In conclusion, the major finding of our study is that in overweight men, in addition to an increased alpha(2)-antilipolytic effect, the lipid mobilization in subcutaneous adipose tissue that persists during exercise under beta-blockade is not dependent on catecholamine action. On the basis of correlation findings, it seems to be related to a concomitant exercise-induced rise in plasma ANP when exercise is performed under tertatolol intake and a decrease in plasma insulin.
INSERM U858-I2MR, Institut de Médecine Moléculaire de Rangueil, 1 Ave. Jean Poulhès, Toulouse Cedex 4, France.
Cedric
C
Moro
Fabien
F
Pillard
Isabelle
I
de Glisezinski
Eva
E
Klimcakova
Francois
F
Crampes
Claire
C
Thalamas
Isabelle
I
Harant
Marie-Adeline
MA
Marques
Max
M
Lafontan
Michel
M
Berlan
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001786:Blood Glucose / Q000378:metabolism; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005990:Glycerol / Q000097:blood / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism; D008053:Lipid Mobilization / Q000187:drug effects / Q000502:physiology*; D008297:Male; D050177:Overweight / Q000378:metabolism*; D010646:Phentolamine / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D050151:Subcutaneous Fat / Q000187:drug effects / Q000378:metabolism*; D013876:Thiophenes / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D001786:Blood Glucose; D007328:Insulin; D011412:Propanolamines; D013876:Thiophenes; D009320:Atrial Natriuretic Factor; C005632:tertatolol; D005990:Glycerol; D010646:Phentolamine