Bladé C, Arola L, Alemany M
Departament d'Enginyeria Quimica i Bioquimica, Facultat de Ciéncies Quimiques, Universitat de Barcelona, Tarragona, Spain.
Arch Int Physiol Biochim. 1988 Dec;96(5):201-9. doi: 10.3109/13813458809075945.
The infusion of ether anesthaetized rats with 0.2 M (1 mmols in total) ammonium acetate or glutamine were compared with the infusion of 0.2 M NaCl. The levels of circulating glucose, amino acids, lactate, urea and ammonium were measured as well as liver glycogen and tissue amino acids and the liver and muscle activities of carbamoyl phosphate synthetases I and II, glutamate dehydrogenase, glutamine synthetase and adenylate deaminase. Neither treatment altered the glucose and glycogen homeostasis. The infusion of ammonium did not result in increases in circulating ammonium, but resulted in increased circulating urea after a short delay; the infusion of glutamine resulted also in urea production but much later on. Glutamine infusion also resulted in increased tissue free amino-acid levels. There was little alteration in enzyme activities, except for decreased glutamine synthetase and adenylate deaminase activity in muscle of glutamine-infused rats and higher tissue carbamoyl phosphate synthetase II. The results agree with a fast removal of infused ammonium, and maintenance of glutamine, with their channeling towards urea production at a rate comparable with that of infusion, that did not alter significantly the homeostasis of the experimental animals.
将0.2 M（总量1 mmol）醋酸铵或谷氨酰胺注入乙醚麻醉的大鼠，并与注入0.2 M氯化钠的大鼠进行比较。测量了循环中的葡萄糖、氨基酸、乳酸、尿素和铵的水平，以及肝糖原、组织氨基酸以及肝脏和肌肉中氨甲酰磷酸合成酶I和II、谷氨酸脱氢酶、谷氨酰胺合成酶和腺苷脱氨酶的活性。两种处理均未改变葡萄糖和糖原的稳态。注入铵后，循环中的铵没有增加，但在短暂延迟后循环中的尿素增加；注入谷氨酰胺也导致尿素生成，但时间要晚得多。注入谷氨酰胺还导致组织游离氨基酸水平升高。酶活性几乎没有变化，只是注入谷氨酰胺的大鼠肌肉中谷氨酰胺合成酶和腺苷脱氨酶活性降低，以及组织氨甲酰磷酸合成酶II活性较高。结果表明，注入的铵能快速清除，并维持谷氨酰胺水平，它们以与注入速度相当的速率导向尿素生成，这并未显著改变实验动物的稳态。
