EFFECTS OF SPONTANEOUS WHEEL RUNNING ON THE RATE OF FATTY ACID SYNTHESIS IN VIVO / 体力科学

ABSTRACT

Effects of spontaneous wheel running on the rate of fatty acid synthesis in viva was studied. Adult female rats were housed in a sedentary condition or free access to a running wheel for 50 days.<BR>The weight gain of the exercising rats was slower than that of the sedentary rats. At the end of 50 days free access to the running wheel, the body weight of sedentary rats was 285±8g and that of the exercising rats was 263±5g. This difference in body weight between sedentary and exercising rats was mainly due to the difference in an amount of body fat (47±5g vs. 31±3g) . The weight of the parametrial adipose tissue of the sedentary rats was 6.1±1.0 g and that of the exercising rats was 2.8± 0.6 g. The diameter of adipocytes of the exercising rats was smaller than that of the sedentary rats (118±9 μm v.s. 150±7 μm) on the other hand there was no significant difference in adipocyte number between the both groups.<BR>At the end of 50 days free access to a running wheel, the rats were injected intraperitoneally <SUP>3</SUP>H<SUB>2</SUB>O to determine the total rate of fatty acid synthesis. The rats were killed 60 minutes after the injection and the amount of <SUP>3</SUP>H incorporated from <SUP>3</SUP>H<SUB>2</SUB>O into fatty acid in a parametrial adipose tissue and liver was determined. The amount of fatty acid synthesized was calculated from the amount of <SUP>3</SUP>H incorporated into fatty acid and the specific radioactivity of water in serum. Because it is known that the rate of fatty acid synthesis fluctuates within a day, we measured the rate of fatty acid synthesis during the light and dark period. The rate of fatty acid synthesis in adipose tissue of the exercising rats was higher than that of the sedentary rats in both light and dark period (light period 21.8±5.2 v.s. 6.6±1.7, dark period 53.5±10.3 vs. 18.2±5.2μ mol C-2 units/tissue/h) . The rate of fatty acid synthesis in liver of the exercising rate was higher than that of the sedentary rats during dark period (480± 79 v.s. 283 ±50 μ mol C-2 units/tissue/h) . During the light period, there was a same tendency in fatty acid synthesis in the liver (230±30 v.s. 197±44) .