Lack of a2-adrenergic antilipolytic effect during exercise in subcutaneous adipose
tissue of trained men.
Glisezinski, I. De, F. Marion-Latard, F. Crampes, M. Berlan, J. Hejnova, J. M. Cottet-
Emard, V. Stich, and D. Rivière.
1Laboratoire des Adaptations de l'Organisme à l'Exercice Musculaire, CHU Purpan,
31059 Toulouse Cedex; 2Laboratoire de Pharmacologie Médicale et Clinique, Faculté de
Médecine, 31073 Toulouse Cedex; 3Institut National de la Santé et de la Recherche
Médicale (INSERM, Unité 317), Université Paul Sabatier, 31403 Toulouse Cedex;
4Laboratoire de Physiologie de l'Environnement, Université Claude Bernard Lyon
Grange Blanche, 69373 Lyon Cedex 08, France; and 5Department of Sport Medicine,
Charles University, 100 00 Prague 10, Czech Republic
APStracts 8:0341A, 2001.
The aim of this study was to investigate the involvement of the antilipolytic a2-
adrenergic receptor (AR) pathway in the regulation of lipolysis during exercise in
subcutaneous abdominal adipose tissue (SCAAT). Seven trained men and 15 untrained
men were studied. With the use of microdialysis, the extracellular glycerol concentration
was measured in SCAAT at rest and during 60 min of exercise at 50% of maximal
oxygen consumption. One microdialysis probe was perfused with Ringer solution, the
other was supplemented with phentolamine (a2-AR antagonist). No differences in
baseline extracellular or plasma glycerol concentrations were found between the two
groups. The exercise-induced extracellular and plasma glycerol increase was higher in
trained compared with untrained subjects (P < 0.05). Addition of phentolamine to the
perfusate enhanced the exercise-induced response of extracellular glycerol in untrained
subjects but not in trained subjects. The exercise-induced increase in plasma
norepinephrine and epinephrine concentrations and the decrease in plasma insulin was
not different in the two groups. These in vivo findings demonstrate higher exercise-
induced lipolysis in trained compared with untrained subjects and show that, in trained
subjects, the a2-mediated antilipolytic action is not involved in the regulation of lipolysis
in SCAAT during exercise.
Received 10 May 2000; accepted in final form 20 May 2001
APS Manuscript Number A0471-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 29 June 2001