Ni Yihan, Lai Xiangdeng, Li Lin, Sun Jingquan, Qu Yaqian, Chen Siyu, Zhang Hao
1Institute of Sports Science, Sichuan University, Chengdu, China.
2School of Physical Education and Sports, Sichuan University, Chengdu, China.
Physiol Int. 2024 Jan 31;111(1):124-141. doi: 10.1556/2060.2023.00238. Print 2024 Mar 21.
Lactate, a metabolite of exercise, plays a crucial role in the body. In these studies, we aimed to investigate the role of G protein-coupled receptor 81 (GPR81), a specific receptor for lactate, in regulating lipid storage in the gastrocnemius muscle of rats. To achieve this, we measured the impact of sodium 3-hydroxybutyrate (3-OBA) concentration and time on the cAMP-PKA signaling pathway in the gastrocnemius muscles of rats. Our investigation involved determining the effects of administering 3-OBA at a concentration of 3 mmol L-1 just 15 min before exercise. As expected, exercise led to a notable increase in intramuscular lactate concentration in rats. However, injecting 3-OBA prior to exercise yielded intriguing results. It not only further augmented the cAMP-PKA signaling pathway but also boosted the expression of lipolysis-related proteins such as hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL). Simultaneously, it decreased the expression of fat-synthesizing proteins, including acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS), while increasing the protein expression of cytochrome c oxidase subunit Ⅳ(COX Ⅳ) and the activity of citrate synthetase (CS). Unfortunately, there was no significant change observed in intramuscular triglyceride (IMTG) content. In summary, our findings shed light on the role of lactate in partially regulating intramuscular triglycerides during exercise.
乳酸作为运动的一种代谢产物，在体内发挥着关键作用。在这些研究中，我们旨在探究乳酸的特异性受体——G蛋白偶联受体81（GPR81）在调节大鼠腓肠肌脂质储存中的作用。为实现这一目标，我们测量了3-羟基丁酸钠（3-OBA）浓度和时间对大鼠腓肠肌中cAMP-PKA信号通路的影响。我们的研究包括确定在运动前15分钟给予3 mmol L-1浓度的3-OBA的效果。正如预期的那样，运动导致大鼠肌肉内乳酸浓度显著增加。然而，在运动前注射3-OBA产生了有趣的结果。它不仅进一步增强了cAMP-PKA信号通路，还提高了激素敏感性脂肪酶（HSL）和脂肪甘油三酯脂肪酶（ATGL）等脂肪分解相关蛋白的表达。同时，它降低了包括乙酰辅酶A羧化酶（ACC）和脂肪酸合酶（FAS）在内的脂肪合成蛋白的表达，同时增加了细胞色素c氧化酶亚基Ⅳ（COXⅣ）的蛋白表达和柠檬酸合酶（CS）的活性。遗憾的是，肌肉内甘油三酯（IMTG）含量没有观察到显著变化。总之，我们的研究结果揭示了乳酸在运动过程中对肌肉内甘油三酯的部分调节作用。
