Dhahbi J M, Mote P L, Wingo J, Tillman J B, Walford R L, Spindler S R
Department of Biochemistry, University of California, Riverside 92521, California, USA.
Am J Physiol. 1999 Aug;277(2):E352-60. doi: 10.1152/ajpendo.1999.277.2.E352.
We characterized the effects of calorie restriction (CR) on the expression of key glycolytic, gluconeogenic, and nitrogen-metabolizing enzymes in mice. Of the gluconeogenic enzymes investigated, liver glucose-6-phosphatase mRNA increased 1.7- and 2. 3-fold in young and old CR mice. Phosphoenolpyruvate carboxykinase mRNA and activity increased 2.5- and 1.7-fold in old CR mice. Of the key glycolytic enzymes, pyruvate kinase mRNA and activity decreased approximately 60% in CR mice. Hepatic phosphofructokinase-1 and pyruvate dehydrogenase mRNA decreased 10-20% in CR mice. Of the genes that detoxify ammonia generated from protein catabolism, hepatic glutaminase, carbamyl phosphate synthase I, and tyrosine aminotransferase mRNAs increased 2.4-, 1.8-, and 1.8-fold with CR, respectively. Muscle glutamine synthetase mRNA increased 1.3- and 2. 1-fold in young and old CR mice. Hepatic glutamine synthetase mRNA and activity each decreased 38% in CR mice. These CR-induced changes are consistent with other studies suggesting that CR may decrease enzymatic capacity for glycolysis and increase the enzymatic capacity for hepatic gluconeogenesis and the disposal of byproducts of muscle protein catabolism.
我们研究了热量限制（CR）对小鼠关键糖酵解、糖异生和氮代谢酶表达的影响。在所研究的糖异生酶中，年轻和老年CR小鼠肝脏葡萄糖-6-磷酸酶mRNA分别增加了1.7倍和2.3倍。老年CR小鼠磷酸烯醇式丙酮酸羧激酶mRNA和活性分别增加了2.5倍和1.7倍。在关键糖酵解酶中，CR小鼠丙酮酸激酶mRNA和活性降低了约60%。CR小鼠肝脏磷酸果糖激酶-1和丙酮酸脱氢酶mRNA降低了10%-20%。在将蛋白质分解代谢产生的氨解毒的基因中，肝脏谷氨酰胺酶、氨基甲酰磷酸合成酶I和酪氨酸转氨酶mRNA在CR条件下分别增加了2.4倍、1.8倍和1.8倍。年轻和老年CR小鼠肌肉谷氨酰胺合成酶mRNA分别增加了1.3倍和2.1倍。CR小鼠肝脏谷氨酰胺合成酶mRNA和活性均降低了38%。这些CR诱导的变化与其他研究一致，表明CR可能降低糖酵解的酶活性，并增加肝脏糖异生以及肌肉蛋白质分解代谢副产物处理的酶活性。
