title: Apparent involvement of opioid peptides in stress-induced enhancement of tumor growth.
abstract: Exposure to stress has been associated with alterations in both immune function and tumor development in man and laboratory animals. In the present study, we investigated the effect of a particular type of inescapable footshock stress, known to cause an opioid mediated form of analgesia, on survival time of female Fischer 344 rats injected with a mammary ascites tumor. Rats subjected to inescapable footshock manifested an enhanced tumor growth indicated by a decreased survival time and decreased percent survival. This tumor enhancing effect of stress was prevented by the opiate antagonist, naltrexone, suggesting a role for endogenous opioid peptides in this process. In the absence of stress, naltrexone did not affect tumor growth.
mesh_terms: D000230:Adenocarcinoma / Q000150:complications / Q000503:physiopathology*; D000818:Animals; D003692:Delayed-Action Preparations; D004597:Electroshock; D004723:Endorphins / Q000502:physiology*; D005260:Female; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000150:complications / Q000503:physiopathology*; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000627:therapeutic use*; D051381:Rats; D011916:Rats, Inbred F344; D013315:Stress, Psychological / Q000150:complications / Q000503:physiopathology*
chemical_list: D003692:Delayed-Action Preparations; D004723:Endorphins; D009270:Naloxone; D009271:Naltrexone