Increased hepatic glucose production response to glucagon in
trained subjects.
Drouin, Rojean, Carole Lavoie, Jose Bourque, Francine Ducros, Danielle
Poisson, and Jean-Louis Chiasson.
Research Group on Diabetes and Metabolic Regulation Research
Center, CHUM, Htel-Dieu Pavilion Department of Medicine, University
of Montreal Montreal (Quebec) H2W 1T8, Canada. Department of Physical
Activities Universite du Quebec [alpha] Trois-Rivires Trois-Rivires
(Qu[theta]bec) G9A 5H7, Canada
APStracts 4:0213E, 1997.
The study was designed to characterize the impact of endurance
training on hepatic response to glucagon. We measured the effect of
glucagon on hepatic glucose production (HGP) in resting trained
(n[acute]a=[acute]a8) and untrained (n[acute]a=[acute]a8) healthy
male subjects (VO2max: 65.9[acute]a [acute]a1.6 vs 46.8[acute]a
[acute]a0.6[acute]amlO2[grave]okg-1[grave]omin-1 respectively,
p[acute]a<[acute]a0.001). Endogenous insulin and glucagon were
suppressed by somatostatin (SRIF) infusion (450[acute]a(g/hr) over 4
hours. Insulin (0.15[acute]amU[grave]okg-1[grave]omin-1) was infused
throughout the study and glucagon (1.5[acute]ang[grave]okg
-1[grave]omin-1) over the last 2 hours. During the latter period,
plasma glucagon and insulin remained constant at 138.2[acute]a 3.1 vs
145.3[acute]a [acute]a2.1[acute]ang(L-1 and at 95.5[acute]a
[acute]a4.5 vs 96.2[acute]a [acute]a1.9[acute]apmol(L-1 in trained
and untrained subjects respectively. Plasma glucose increased and
peaked at 11.4[acute]a [acute]a1.1[acute]ammol/l in trained subjects
and at 8.9[acute]a [acute]a0.8[acute]ammol/l in untrained subjects
(p[acute]a<[acute]a0.001). During the first hour of glucagon
stimulation, the peak increase in HGP was 15.8[acute]a
[acute]a2.8[acute]a mol[grave]okg-1[grave]omin-1 in trained subjects
compared to 7.4[acute]a [acute]a1.6[acute]a mol[grave]okg
-1[grave]omin-1 in untrained subjects (p[acute]a<[acute]a0.01) over
the first hour and declined gradually to 6.8[acute]a
[acute]a2.8[acute]a mol[grave]okg-1[grave]omin-1 and 4.9[acute]a
[acute]a1.4[acute]a mol[grave]okg-1[grave]omin-1 by the end of the
second hour. In conclusion, these observations indicate that
endurance training is associated with an increase in hepatic glucose
production in response to physiologic level of glucagon, thus
suggesting an increase in hepatic glucagon sensitivity.
Received 1 April 1997; accepted in final form 19 September 1997.
APS Manuscript Number E150-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997