The Effect of Exercise on the Conversion Rate of Ingested Glueose to Glycogen in the Hindlimb Skeletal Muscles in Rats

흰위에서 운동부하후 경구투여한 Glucose가 특성이 다른 골격근에서 Glycogen으로 합성되는 속도

In the present study the effect of exercise on the conversion rate of ingested glucose to glycogen in the different types of hindlimb skeletal muscles in Sprague-Dawley male rats was studied. The amounts of synthetized glycogen from ingested glucose of fast-twitch white(WV), fast-twitch red(RV), mixed type of fast-twitch white and red(EDL), and slow-twitch(SOL) muscles were determined at 30 and 90 min. after ingestion of 25% glucose solution which contained $^{14}C$-glucose($2m{\ell}(1uCi)$/100gm B. W.)in control and exercise loaded rats. The result was summarized as follows : The about 55% at 30 min. and 70% at 90 min. after glucose ingestion were absorbed from gastrointestinal tract. This result shows no effects of exercise on absorption rate from gastrointestinal tract. The amount of synthetized glycogen of SOL from ingested glucose at 30 and 90 min. after glucose ingestion were highest, whether WV were lowest in hindlimb skeletal muscles in control and exercise loaded rats. In the exercise loaded rats, the amounts of synthetized glycogen of SOL, RV, and EDL at 90 min. after glucose ingestion was much higher than control rats, but not different in WV between exercise-loaded and control rats. At 30 min. after glucose ingestion, only SOL of exercise loaded rats was higher than control rats. In the control rat, the synthesis of glycogen was almost completed during initial 30 minutes. On the other hand, in the exercise loaded rat, except WV was opposite result of control rats, i. e., amounts of synthetized glycogen were major during late period. The amount of synthetized glycogen of liver at 30 and 90 min. after glucose ingestion in exercise loaded rats was higher than control rats. The rate of glycogen synthesis in control and exercise loaded rats were higher between 30-90 minute than initial 30 minute.

Sprague-Dawley중 흰쥐에게 $^{14}C$-glucose가 들어있는 glucose용액을 경구 투여한 후 특성이 다른 골격근에서 투여 glucose가 glycogen으로 합성된 양과 운동부하가 이에 미치는 효과를 관찰한 본 연구 결과를 요약하면 다음과 같다. Glucose 경구투여 후 위장관에서의 흡수율은 운동부하군 및 대조군 모두 30분에 55% 정도였고 90분후에는 70% 가량이 흡수되었다. 투여 glucose로부터 유래된 골격근 glycogen 합성량은 양군 모두 SOL에서 가장 높았으며 WV가 가장 낮았다. 운동부하군이 대조군에 비하여 glycogen 합성량이 많았으며 특히 SOL, RV에서 현저히 높았다. 운동부하군에서 투여 glucose로부터 합성된 glycogen의 양이 90분후에는 SOL, RV 그리고 EDL에서는 대조군보다 월등히 많았으나 WV에서는 차이가 없었으며 30분경에는 SOL만이 유의하게 높았다. 투여 glucose에서 유래한 glycogen 합성속도는 운동부하군에서 WV를 제외한 모든 근육에서 초기 30분보다 후반 60분이 월동이 빨랐으나 SOL을 제외한 대조군과 WV는 처음 30분동안에 대부분의 glycogen이 합성되었다. 간장에서는 투여 glucose로부터 합성된 glycogen양은 양군 모두에서 초기 30분동안에는 합성량이 미미했으나 운동부하군의 90분동안에는 30분에 비하여 무려 20여배의 증가를 보였다.