[The study of neuro-adrenolysis of pituitary gland on cancer pain and experimental approach to reveal its mechanism of pain relief].

Neuro-adrenolysis of the pituitary gland by injection of pure alcohol was done to control intractable pain associated with wide-spread cancer, and pituitary functions were measured before and after the injection. Of a series of 46 patients undergoing a total of 57 neuro-adrenolysis of the pituitary gland, 22 (38.6%) of these procedures obtained complete pain relief 22 (38.6%) showed improvement, and the remaining 13 (22.8%) no effect. Hormonal changes of pituitary gland were not same among the cases and there was no correlation between hormonal changes and the occurrence of pain relief. Experimental study was done to investigate the effect of hypophysectomy and intracerebroventricular injection of AVP on pain threshold in rats. The study revealed that hypophysectomy and ventricular injection of AVP dose dependently raised pain threshold and these effects were inhibited by naloxone. These facts suggest that the analgesic effects of hypophysectomy and AVP injection into cerebral ventricle are mediated by beta-endorphin.