Malaisse W J, Sener A
Acta Biol Med Ger. 1981;40(1):3-8.
Isolated pancreatic rat islets deprived of exogenous nutrients maintain a sustained rate of O2 consumption. Glucose exerts little effect upon the utilization of endogenous nutrients. It is proposed that, under physiological conditions circulating L-glutamine represents a major fuel to cover the basal energy expenditure of the islets. Exogenous L-glutamine, which is actively metabolized in the islets, also provides an adequate substrate for the reaction catalyzed by glutamate dehydrogenase. L-glutamine dramatically enhances insulin release evoked by those amino acids which cause allosteric activation of the latter enzyme, e.g. L-leucine or b(-)BCH.
缺乏外源性营养物质的离体大鼠胰岛能维持持续的耗氧率。葡萄糖对内源性营养物质的利用影响很小。有人提出，在生理条件下，循环中的L-谷氨酰胺是满足胰岛基础能量消耗的主要燃料。在胰岛中被积极代谢的外源性L-谷氨酰胺，也为谷氨酸脱氢酶催化的反应提供了充足的底物。L-谷氨酰胺能显著增强由那些引起该酶别构激活的氨基酸（如L-亮氨酸或b(-)BCH）所诱发的胰岛素释放。
