AJP - Endocrinology and Metabolism, Vol 251, Issue 3 251-E257, Copyright © 1986 by American Physiological Society
Lipoprotein lipase in adipose tissues of exercise-trained, cold-acclimated rats
Y. Deshaies, D. Richard and J. Arnold
The combined effects of exercise training and cold acclimation on serum
lipids and on the activity of lipoprotein lipase (LPL) in epididymal white
(WAT) and interscapular brown adipose tissues (BAT) of the rat were
evaluated. Sedentary and exercise-trained (treadmill) rats were housed and
trained at either 24 or 4 degrees C for 45 days. Although neither treatment
given alone influenced serum total cholesterol, exercise training in the
cold resulted in a 54% increase in this variable. Serum triglycerides were
lowered to 80% of control values by exercise training and to 44% of control
by cold acclimation. Both treatments resulted in lower insulin and
thyroxine concentrations, while triiodothyronine levels were unaffected.
Total LPL activity in WAT was increased twofold by exercise training at
both temperatures, whereas cold acclimation stimulated WAT LPL activity to
a lesser extent. Exercise training had no overall effect on LPL activity of
BAT, whereas cold acclimation increased the latter in both sedentary (217%)
and trained (420%) animals. These results emphasize the potential
importance of LPL-mediated lipid assimilation in the metabolic events that
lead to energy production in response to environmental stresses and lend
support to the notion that the regulation of LPL activity is tissue
specific.
