Interaction of morphine and steroid hormones in the postirradiation disease in rats.

Male Wistar rats were irradiated with a single 600 R dose of X rays and then treated for 3 or 6 days with intraperitoneal injections of steroid hormones. In both irradiated and non-irradiated rats the morphine analgesia was potentiated after 3, and even more after 6 days of pretreatment with testosterone and hydrocortisone, while the effect of morphine was weaker after pretreatment with estradiol and desoxycortone. The results correlate with an increase or decrease of the morphine level in the brain. The results cannot be explained by changes in the activity of beta-glucuronidase.