[The dynamics of beta-endorphins in plasma in the peri- and intraoperative phase of radical gynecologic surgery].

Stress produced by anaesthesia and operation results in the activation of regulatory processes aimed at maintaining homoeostasis. Numerous studies point to the opioid system acting in the adaptation process as a reserve force in homoeostatic maintenance. We made peri- and intraoperative radioimmunological measurements of the beta-endorphin, a c-terminal fragment of the pro-opiomelanocortin. In spite of the latent stress prevalent in patients before the operation, there was no change in the concentration of beta-endorphin in the plasma before the operation. As soon as the operation began a marked increase in the beta-endorphin concentration was observed, reaching a peak at the end of the operation. Postoperatively, the beta-endorphin level rapidly decreased and the initial value was attained within 24 hours. Our studies provide evidence that there is a protective mechanism guarding the organism against external disturbing factors in stress situations.