The analysis of methionine and leucine enkephalins in relationship to the immune response in trauma patients by high pressure liquid chromatography and microspectrophotometric techniques

Abstract

Numerous reports on the affect of enkephalins (endogenous opiates) on the immune system have recently appeared in literature. Most of these are studies which center on the site of production, effects on the nervous system, and their role in the modulation of pain. However, none of these studies report on the interaction of effect of these molecules on circulating lymphocytes. The present study presents data on serum methionine and leucine enkephalin levels and their affects on circulating lymphocytes. Twelve emergency room trauma patients were studied over a three day period. Serum enkephalin levels were assayed by means of high pressure liquid chromatography, while lymphocyte activity was accessed by measurements of DNA concentration and template activity coupled with protein synthetic activity. The latter studies were done by means of quantitative cytophotometry. Results of this study demonstrated that as levels of methionine enkephalin increased, DNA concentration, or synthetic activity, and protein synthesis decreased. Leucine enkephalin had the opposite effect. This suggests that methionine and leucine enkephalins bind to different receptors on the surface of circulating lymphocytes. Emergency patients' response to treatment regarding post-trauma stabilization of their condition significantly affected the levels of circulating enkephalins over the periods studied and thus the synthetic activity of circulating lymphocytes.