RESUMO
We investigated the effects of feeding a large meal to female rats (n = 66) just before or just after voluntary wheel running on energy metabolism during a final endurance exercise test. The rats were divided into three groups ; one fed a large meal just before exercise (BE), one fed a large meal just after exercise (AE), and one fed <I>ad libitum</I> (AD) . The rats were allowed to run voluntarily from 20 : 00 to 07 : 00 h. The BE group were given a large meal (more than 12 g) between 19 : 00 and 20: 00 h and a small meal (3 g) between 07 : 00 and 08 : 00 h. The AE group were given a large meal (more than 12 g) between 07 : 00 and 08 : 00 h and a small meal (3 g) between 19 : 00 and 20 : 00 h. After 4 weeks, 6 rats in each group were sacrificed at 22 : 00 h, and 12 rats in each group were sacrificed after 30 min starting from 22 : 00 h at 15 m/min (n=6) or 35 m/min (n=6) on a rodent treadmill (0° grade) . Four rats in each group were sacrificed after 30 min starting from 22 : 00 h at rest on the treadmill as a control. The plasma free fatty acid (FFA) and glycerol concentrations increased significantly during low-speed exercise in the AD group, and during higher-speed exercise in all groups. The liver glycogen concentration was significantly greater in the AE group than in the other groups at rest, and decreased significantly during exercise at both speeds in the AD group, but not in the BE and AE groups. The gastrocnemius muscle glycogen concentration was decreased significantly during exercise at both speeds in the AD group, and at high speed in the BE and AE groups.<BR>These results indicate that intake of a large meal just after exercise can store a high level of liver glycogen at the beginning of exercise than <I>ad libitum</I> feeding or large meal intake just before exercise, and expend plasma FFA in muscle during exercise compared with <I>ad libitum</I> feeding. This suggests that large meal intake just after exercise contributes to improvement of metabolic capacity in endurance exercise with enhanced liver glycogen sparing.
RESUMO
The present study was carried out to elucidete whether the accumulation of triglyceride (TG) in rat liver during fasting was stimulated by swimming. Male Wistar rats were divided into three groups; C: control, 24 F: 24 hour-fasted and 48 F: 48 hour-fasted. These animals were required to swim for 120 min.<BR>In rats with both 24F and 48F, the liver glycogen contents did not change during swimming. The level of TG in rat liver was higher in 24 F and 48 F rats than the control group, and the exercise significantly affected the liver TG in each group. There was significant correlation betweem the level of TG in rat liver and the plasma free fatty acid (FFA) concentration (r=0.681, p<0.01) . However, although plasma TG did not change during exercise in each group, the TG secretion rate (TGSR) of the 48 F group was significantly lower than that of the C and 24F groups (p<0.01) .<BR>These results provide evidence that exercise may result in the accumulation of TG in liver during fasting and suggest that the process not only depends on the surplus supply of FFA, but also inhibits very low density lipoprotein-TG secretion from liver.