Effects of major and minor surgery on plasma glutamine and cytokine levels.

The plasma levels of glutamine and cytokines have been measured frequently in patients before, during, and after elective abdominal aortic aneurysm surgery ("major surgery") or inguinal hernia repair ("minor surgery"). The plasma glutamine level declined rapidly following major surgery and remained markedly below preoperative levels until at least 7 days after surgery. This response of the plasma glutamine levels was significantly correlated with the production of interleukin 6 but not with that of interleukin 1, tumor necrosis factor, or interferon gamma. In contrast, following minor surgery, the plasma glutamine level was unchanged and the elaboration of interleukin 6 was attenuated. The decrease in the plasma glutamine level following major surgery may contribute to the state of immunosuppression, which follows major surgery, and the relationship between amino acid and cytokine metabolism is worthy of further study.