Activation of triacylglycerol lipase in the fat body of a beetle by adipokinetic hormone
Activation of triacylglycerol lipase in the fat body of a beetle by adipokinetic hormone
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DOI：
10.1016/j.ibmb.2005.01.010
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发表时间：
2005-05-01
影响因子：
3.8
通讯作者：
Gäde, G
中科院分区：
文献类型：
--
作者：
Auerswald, L;Siegert, KJ;Gäde, G
内源八肽激素Melme-CC对Pachnoda sinuata脂肪体三酰甘油脂肪酶的激活及对脯氨酸合成的促进作用（pQLNYSPDWa），其属于昆虫脂肪运动激素家族，进行了研究，并且研究了两个事件的相关性。三酰甘油脂肪酶在甲虫脂肪体中的活性高于美洲大蠊脂肪体中的活性，但低于飞蝗脂肪体中的活性。甲虫的三酰甘油脂肪酶被激活：（a）注射合成Melme-CC和（B）飞行刺激。Melme-CC对脂肪酶的激活具有时间依赖性。注射ept-cAMP激活脂肪体中的三酰甘油脂肪酶，并以丙氨酸为代价导致血淋巴中脯氨酸浓度增加。相反，注射F-肌醇-1，4，5-磷酸不影响脂肪酶的活化状态，也不影响血淋巴中氨基酸的水平。高剂量的章鱼胺不会激活脂肪酶。此外，脂肪体脂肪酶的活性和血淋巴中的脯氨酸浓度都遵循昼夜节律：这两个参数是在早上高，而在晚上低。当通过颈部结扎阻止从心体释放的Melme-CC转移到胸部/腹部时，脂肪酶的活性以及循环脯氨酸水平较低。回归分析表明，三酰甘油脂肪酶活性与血淋巴中脯氨酸浓度呈正相关，与血淋巴中丙氨酸浓度呈负相关，说明Melme-CC对脂肪体三酰甘油脂肪酶的激活促进了脯氨酸的合成。脯氨酸是甲虫动力飞行活动的主要底物之一。(c)2005爱思唯尔有限公司保留所有权利。
The activation of triacylglycerol lipase and the stimulation of proline synthesis in the fat body of the fruit beetle Pachnoda sinuata by the endogenous octapeptide hormone Melme-CC (pQLNYSPDWa), which belongs to the family of insect adipokinetic hormones, were studied, and the correlation of both events investigated.At rest, the activity of triacylglycerol lipase in the fat body of the beetle was higher than in the fat body of the American cockroach, Periplaneta americana, but lower than in the migratory locust, Locusta migratoria. Triacylglycerol lipase of the beetle is activated by: (a) injection of synthetic Melme-CC and (b) the stimulus of flight. Activation of lipase by Melme-CC is time-dependent. Injection of ept-cAMP activates triacylglycerol lipase in the fat body and causes an increase in the concentration of proline in the haemolymph at the expense of alanine. In contrast, injection of F-inositol-1,4,5-phosphate does not affect the activation state of lipase, nor the levels of amino acids in the haemolymph. High doses of octopamine do not activate lipase. Furthermore, activity of fat body lipase and proline concentration in the haemolymph both follow a circadian rhythm: both parameters are high in the morning, whereas they are low in the evening. When transfer of Melme-CC, released from the corpora cardiaca, to the thorax/abdomen is prevented by neck-ligation, the activity of lipase, as well as the circulating proline levels are low. Regression analysis revealed that activity of triacylglycerol lipase is positively correlated to proline concentration in the haemolymph, whereas there is a negative correlation of the enzyme activity and alanine level in the haemolymph.From these results we conclude that the activation of fat body triacylglycerol lipase by Melme-CC in P. sinuata stimulates proline synthesis. Proline is one of the major substrates to power flight activity in the beetle. (c) 2005 Elsevier Ltd. All rights reserved.