Arriarán Sofía, Agnelli Silvia, Remesar Xavier, Alemany Marià, Fernández-López José Antonio
Department of Nutrition and Food Science, Faculty of Biology, University of Barcelona, Barcelona, Spain.
Food Funct. 2016 Mar;7(3):1554-63. doi: 10.1039/c5fo01503k.
Under high-energy diets, amino acid N is difficult to dispose of, as a consequence of the availability of alternative substrates. We found, recently, that WAT contains a complete functional urea cycle, we analyzed the possible overall changes in the WAT urea cycle (and other-related amino acid metabolism gene expressions) in rats subjected to a cafeteria diet. Adult female Wistar rats were fed control or simplified cafeteria diets. Samples of WAT sites: mesenteric, periovaric, retroperitoneal and subcutaneous, were used for the estimation of all urea cycle enzyme activities and gene expressions. Other key amino acid metabolism gene expressions, and lactate dehydrogenase were also measured. Subcutaneous WAT showed a differentiated amino acid metabolism profile, since its cumulative (whole site) activity for most enzymes was higher than the activities of the other sites studied. After one month of eating an energy-rich cafeteria diet, and in spite of doubling the size of WAT, the transforming capacity of most amino acid metabolism enzymes remained practically unchanged in the tissue. This was not only due to limited changes in the overall enzyme activity, but also a consequence of a relative decrease in the expression of the corresponding genes. Overall, the results of this study support the consideration of WAT as an organ, disperse but under uniform control. The metabolic peculiarities between its different sites, and their ability to adapt to different energy availability conditions only add to the variable nature of adipose tissue. We have presented additional evidence of the significant role of WAT in amino acid metabolism.
在高能饮食条件下，由于存在替代底物，氨基酸氮难以被处理。我们最近发现，白色脂肪组织（WAT）中存在完整的功能性尿素循环，于是我们分析了喂食自助餐饮食的大鼠WAT尿素循环（以及其他相关氨基酸代谢基因表达）可能发生的总体变化。成年雌性Wistar大鼠被喂食对照饮食或简化的自助餐饮食。采集肠系膜、卵巢周围、腹膜后和皮下等部位的WAT样本，用于评估所有尿素循环酶的活性和基因表达。还测量了其他关键氨基酸代谢基因的表达以及乳酸脱氢酶。皮下WAT呈现出不同的氨基酸代谢特征，因为其大多数酶的累积（整个部位）活性高于所研究的其他部位。在食用富含能量的自助餐饮食一个月后，尽管WAT的大小增加了一倍，但该组织中大多数氨基酸代谢酶的转化能力实际上保持不变。这不仅是由于总体酶活性变化有限，也是相应基因表达相对下降的结果。总体而言，本研究结果支持将WAT视为一个分散但受统一控制的器官。其不同部位之间的代谢特性以及它们适应不同能量供应条件的能力，只会增加脂肪组织的多变性。我们提供了更多证据证明WAT在氨基酸代谢中具有重要作用。
