Negative energy balance with exercise in identical twins: plasma
glucose and insulin responses.
Oppert, Jean-Michel, Andr[acute]e Nadeau, Angelo Tremblay, Jean-Pierre
Despr[acute]es, Germain Th[acute]eriault, and Claude Bouchard.
NUTRITION DEPARTMENT, H[circumflex]oTEL-DIEU HOSPITAL, PARIS 75004,
FRANCE, DIABETES RESEARCH UNIT, PHYSICAL ACTIVITY SCIENCES LABORATORY
AND LIPID RESEARCH CLINIC, LAVAL UNIVERSITY, STE FOY, QU[acute]eBEC
G1K 7P4, CANADA
APStracts 3:0222E, 1996.
The effects of long-term (93 days) negative energy balance by means of
exercise with constant energy intake on plasma glucose and insulin
were investigated in 7 pairs of young sedentary male identical twins.
Results showed a significant decrease in fasting (-24%, p <
0.02) and postprandial insulin (-16%, p < 0.05). Fasting and
postprandial plasma glucose and glucagon were not modified. Mean
glucose disposal rate measured during a euglycemic-hyperinsulinemic
clamp performed in 5 twin pairs was increased by 34% (p = 0.13). No
significant intrapair similarity was found for the responses of
fasting and postprandial insulin levels, and of glucose disposal
rate. Changes in glucose disposal rate were significantly greater in
high compared to low losers for CT-measured abdominal visceral fat
(3.0 +/- 1.1 vs. 0.3 +/- 0.5 mg/kg/min, p < 0.05), in spite of
similar losses in total body fat. We conclude that: 1) a long-term
negative energy balance generated by exercise training significantly
reduces plasma insulin levels while insulin sensitivity tends to be
improved; 2) training-induced changes in insulin sensitivity are
associated with changes in abdominal visceral fat; and 3) data from
this experiment conducted with a small number of twin pairs suggest
that the genotype does not seem to be a major determinant of the
changes in insulin levels and sensitivity brought about by negative
energy balance with exercise.
Received 13 May 1996; accepted in final form 27 October 1996.
APS Manuscript Number E238-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996