Beta-endorphins in acute myocardial infarction.

The endogenous peptide B-endorphin (B-EP) is closely connected with different aspects of homeostasis, behavior, and in particular with the perception of pain. The purpose of this study was to investigate the correlation between: the level of plasma B-EP and the intensity of pain in acute myocardial infarction (AMI); and the B-EP and specific enzymes for AMI serum glutamic oxolo-acetic transferase, lactate dehydrogenase, and creatine phosphokinase and some stress hormones (cortisol, growth hormone). Twenty-six patients hospitalized in the CCU for acute MI were studied during the first 72 hours from the onset of symptoms. Seven normal subjects served as controls. Blood was taken for hormone and B-EP evaluation before treating the patients by opiates. Plasma B-EP levels were determined using the protocol of the Immunonuclear Corporation (Stillwater, MN). Statistical analysis of the results showed: Nonsignificant differences between B-EP levels of all MI patients and control group. Unaltered B-EP levels in patients with acute MI suffering from moderate pain. Significant differences in drop of B-EP in the group with most severe pain (p less than 0.025). A tendency toward decreased B-EP in patients suffering from more prolonged pain (greater than 6 hours). Significant negative correlation was shown between B-EP and chest pain intensity (0-4 graduation) (r = 0.8, p less than 0.01); lactate dehydrogenase (r = 0.7, p less than 0.01); serum glutamic oxolo-acetic transferase (r = 0.6, p less than 0.01); creatine phosphokinase (r = 0.6, p less than 0.05; plasma cortisol level (r = 0.5, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)