Fentanyl and the beta-endorphin, ACTH and glucoregulatory hormonal response to surgery.

The effect of the supplementation of nitrous oxide-oxygen anaesthesia with either fentanyl 15 micrograms kg-1 or 0.5% halothane on the beta-endorphin, ACTH, glucoregulatory hormonal and metabolic response to pelvic surgery was investigated. Fentanyl inhibited the increases in circulating beta-endorphin, ACTH, growth hormone, cortisol and glucose concentrations found in the patients receiving halothane. Changes in circulating beta-endorphin concentrations during surgery probably reflect alterations in pituitary secretion and appear to have no major metabolic effects. The suppression of pituitary secretion persisted for at least 4 h after the start of surgery.