Evidences of Basal Lactate Production in the Main White Adipose Tissue Sites of Rats. Effects of Sex and a Cafeteria Diet
Evidences of Basal Lactate Production in the Main White Adipose Tissue Sites of Rats. Effects of Sex and a Cafeteria Diet
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DOI：
10.1371/journal.pone.0119572
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发表时间：
2015-03-05
期刊：
影响因子：
3.7
通讯作者：
Alemany, Maria
中科院分区：
文献类型：
--
作者：
Arriaran, Sofia;Agnelli, Silvia;Alemany, Maria
雌性和雄性成年Wistar大鼠被喂食标准食物或简化的自助餐厅饮食一个月。然后，处死大鼠，取腹股沟周围、腹膜后、肠系膜和皮下（腹股沟）4个部位的白色脂肪组织（WAT）并冷冻。测量每个部位的完整WAT重量。分析了关键脂代谢酶和糖代谢酶的基因表达，以及组织和血浆乳酸和乳酸脱氢酶的活性。估计WAT和血浆之间的乳酸梯度。还测定了性别和饮食（间接包括WAT质量）对乳酸水平的影响及其与乳酸脱氢酶活性和基因表达的关系。一个主要结论是，无论部位、饮食或性别，WAT都能产生大量乳酸。乳酸的产生与组织中乳酸脱氢酶的活性直接相关。此外，乳酸脱氢酶活性再次与该酶的基因Ldha和Ldhb的表达直接相关。总之，WAT产生乳酸的能力并不直接依赖于WAT的代谢状态。我们假设，在WAT中，乳酸脱氢酶途径的一个主要功能可能是将多余的可用葡萄糖转化为3C片段，作为限制组织作为底物的自我利用的一种方式，以帮助控制血糖和/或提供短链底物作为其他地方的能量来源。在确定WAT在控制血糖方面的决定性作用之前，必须收集更多的信息，并且必须确定一个更新的葡萄糖-乳酸-脂肪酸循环的完全存在。
Female and male adult Wistar rats were fed standard chow or a simplified cafeteria diet for one month. Then, the rats were killed and the white adipose tissue (WAT) in four sites: perigonadal, retroperitoneal, mesenteric and subcutaneous (inguinal) were sampled and frozen. The complete WAT weight in each site was measured. Gene expression analysis of key lipid and glucose metabolism enzymes were analyzed, as well as tissue and plasma lactate and the activity of lactate dehydrogenase. Lactate gradients between WAT and plasma were estimated. The influence of sex and diet (and indirectly WAT mass) on lactate levels and their relationships with lactate dehydrogenase activity and gene expressions were also measured. A main conclusion is the high production of lactate by WAT, practically irrespective of site, diet or sex. Lactate production is a direct correlate of lactate dehydrogenase activity in the tissue. Furthermore, lactate dehydrogenase activity is again directly correlated with the expression of the genes Ldha and Ldhb for this enzyme. In sum, the ability to produce lactate by WAT is not directly dependent of WAT metabolic state. We postulate that, in WAT, a main function of the lactate dehydrogenase path may be that of converting excess available glucose to 3C fragments, as a way to limit tissue self-utilization as substrate, to help control glycaemia and/or providing short chain substrates for use as energy source elsewhere. More information must be gathered before a conclusive role of WAT in the control of glycaemia, and the full existence of a renewed glucose-lactate-fatty acid cycle is definitely established.