Loading…
Effect of high-altitude acclimation on NEFA turnover and lipid utilization during exercise in rats
1 Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4; and 2 Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5 Relative exercise intensity (or %maximum O 2 consumption, O 2 max ) controls fuel selection at sea level (SL) and after h...
Saved in:
| Published in: | American journal of physiology: endocrinology and metabolism 1999-12, Vol.277 (6), p.E1095-E1102 |
|---|---|
| Main Authors: | , , |
| Format: | Article |
| Language: | English |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | 1 Department of Zoology,
University of British Columbia, Vancouver, British Columbia V6T 1Z4;
and 2 Department of Biology,
University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
Relative exercise intensity (or %maximum
O 2 consumption,
O 2 max )
controls fuel selection at sea level (SL) and after high-altitude acclimation (HA) in rats. In this context we used indirect calorimetry, [1- 14 C]palmitate
infusions, and muscle triacylglycerol (TAG) measurements to determine
1 ) total lipid oxidation,
2 ) the relationship between circulatory nonesterified fatty acid (NEFA) flux and concentration, and
3 ) muscle TAG depletion after
exercise in HA-acclimated rats. Aerobic capacity is decreased in
trained rats after 10 wk of acclimation. Both SL and HA showed the same
relative use of lipids at 60% [62 ± 5% (HA) and 61 ± 3% (SL) of O 2 consumption
( O 2 )] and 80%
[46 ± 6% (HA) and 47 ± 5% (SL) of
O 2 ] of their
respective O 2 max . At
60% O 2 max ,
plasma [NEFA] were higher in HA, but rate of appearance was
essentially the same in both groups (at 30 min, 38 ± 9 vs. 49 ± 6 µmol · kg 1 · min 1
in HA and SL, respectively). At this intensity SL showed no significant decrease in muscle TAG, but in HA it decreased by 64% in soleus and by
90% in red gastrocnemius. We conclude that
1 ) the relative contributions of
total lipid are the same in SL and HA, contrary to differences in
[NEFA], because the relationship between flux rate and
[NEFA] is modified after acclimation, and
2 ) muscle TAG may play a more
important role at HA.
rats; maximum exercise intensity; lipid metabolism; nonesterified
fatty acids; carbohydrates; oxidative fuel; muscle triacylglycerol |
|---|---|
| ISSN: | 0193-1849 1522-1555 |
| DOI: | 10.1152/ajpendo.1999.277.6.E1095 |