Plasma and CSF levels of immunoreactive beta-endorphin in algic peaks of patients with herniated intervertebral discs.

Plasma and CSF levels of beta-Endorphin (beta-End) were measured by radioimmunoassay in three groups of human subjects. The first group consisted of healthy adults, and only plasma beta-End was determined. The second group consisted of patients showing non-painful neurological diseases. The third group consisted of patients suffering from acute pain due to herniated intervertebral discs. In the last two groups, beta-End levels were measured in plasma and CSF. The results showed that plasma levels of beta-End were similar in the first two groups of patients. In contrast, patients with acute pain showed significantly increased levels of beta-End in plasma. CSF levels of beta-End did not show significant differences among the groups. The results suggest that the increase in plasma levels of beta-End was a consequence of the stress produced by acute pain.