장시간 탈진운동 시 골격근 수축 및 에너지대사에서 AQP3의 역할 |
김미자1, 배혜란1, 김동환1, 윤미연1, 박성철2, 소용석1, 김영준1 |
1동아대학교 2부산과학기술대학교 |
A Role of AQP3 in Skeletal Muscle Contraction and Energy Metabolism during a Single Bout of Exhaustive Exercise |
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ABSTRACT |
The purpose of this study was to investigate the difference in the capacity to perform a single bout of exhausting exercise between AQP3 -/-(AQP3 knock-out mice) and AQP3 +/+(wild-type mice), and to compare the concentrations of glycerol and related metabolic parameters in plasma, liver and skeletal muscle after exhaustion. AQP3 -/- and AQP3 +/+ , 16 per each group, were exposed to a single bout of treadmill running at the speed up to 12 m/min with 10° incline until exhaustion. AQP3 -/- exhibited earlier fatigue and decrease in endurance exercise performance with shorter average time to exhaustion than the wild-type control. Both immunohistochemistry and double immunofluorescence staining revealed that AQP3 expressed at the cell surface. Although the longitudinal length and weight of hamstring muscle were reduced in AQP3 -/-, no significant histological difference was observed. At rest, the levels of glucose, glycogen, triglyceride, and glycerol in plasma, liver and skeletal muscle, were lower in AQP3 -/- than AQP3 +/+, intramuscular triglyceride level was higher in AQP3 -/-. After exercise, plasma and muscle glucose, muscle glycogen, and plasma and liver triglyceride levels decreased, whereas plasma and liver glycerol levels increased in both AQP3 -/- and AQP3 +/+ compared to those at rest. However, muscle glycerol as well as liver glycogen concentrations decreased after exercise in wild-type mice, but rather increased in AQP3 -/-. These findings suggest that decreased glycerol efflux from skeletal muscle in AQP3 knock-out mice might result in low exercise capacity due to the limitation in constant energy supply through hepatic gluconeogenesis from glycerol during the prolonged endurance exercise. Therefore, AQP3 may play a role in skeletal muscle fat metabolism and influence the endurance exercise capacity |
Key words:
Aquaporin-3(AQP3), AQP3 knock-out mice, wild-type mice, exhaustive exercise, glycerol, intramuscular triglyceride |
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