饥饿胁迫对大黄鱼激素敏感性脂肪酶和乙酰辅酶A羧化酶mRNA表达及酶活性的影响

激素敏感性脂肪酶（hormone sensitive lipase,HSL）和乙酰辅酶A羧化酶（acetyl-CoA carboxylase,ACC）是脂代谢的关键酶,肌肉和肝脏是鱼类脂代谢的主要场所。为研究饥饿过程中这两种酶的作用,本实验采用实时荧光定量PCR技术以及ELISA技术检测了在35 d饥饿过程中这两种酶在大黄鱼肌肉和肝组织中mRNA表达水平和酶活性的变化。结果显示,饥饿胁迫显著降低大黄鱼肌肉和肝组织中脂肪含量,以及脂肪合成关键酶ACC mRNA表达水平（P<0.05）;显著提高脂肪分解关键酶HSL mRNA表达水平（P<0.05）。饥饿胁迫对肌肉和肝组织中HSL和ACC酶活性均有显著影响（P<0.05）,肌肉和肝组织HSL （相关系数r分别为0.598 2和0.539 6）以及肌肉组织ACC酶活性（r=0.677 7）与对应mRNA表达水平呈中度正相关（0.5 < r < 0.8）,但ACC酶活性在肝组织与其对应的mRNA表达量呈负相关（r=-0.374 0）,提示饥饿胁迫对大黄鱼HSL和ACC的表达存在翻译前和翻译后两种水平的调控。本研究结果可为研究饥饿胁迫对大黄鱼脂类代谢分子层面的影响机制提供依据。

Effects of fasting on the mRNA levels and enzymatic activities of hormone sensitive lipase and acetyl-CoA carboxylase in the large yellow croaker Larimichthys crocea

Hormone sensitive lipase (HSL) and acetyl-CoA carboxylase (ACC) are key enzymes in lipid metabolism. Muscle and liver tissues are major main places. To study the role of the two enzymes during fasting, we detected the mRNA expression and activity changes of HSL and ACC in large yellow croaker muscle and liver tissues during 35 d fasting by real-time fluorescent quantitative PCR (qPCR) and Elisa, respectively. The results showed that fasting significantly decreased fat content and ACC mRNA level (P< 0.05), and increased HSL mRNA expression in both muscle and liver tissues (P<0.05). Moreover, fasting had a significant influence on the activities of HSL and ACC in both muscle and liver tissues of large yellow croaker (P<0.05). Muscle and liver HSL activities were moderately correlated with the corresponding mRNA expression level, as well as ACC in muscle. But liver ACC activity was negatively correlated with the mRNA level. These results suggested that the expression of HSL and ACC were regulated in both pre-translational and post-translational levels during fasting in the large yellow croaker. The results of the present study provide insights into the molecular mechanisms underlying the lipid metabolic response of the large yellow croaker to fasting.