Bombesin enhances experimental carcinogenesis induced in rat colon by 1,2-dimethylhydrazine.
The effects of bombesin on the colonic mucosa and on the incidence, number, size and histology of colon cancers induced by 1,2-dimethylhydrazine (DMH) were studied in Fischer 344 rats. In experiment 1, rats were randomized into three groups to receive either saline or bombesin (10 or 30 micrograms/kg body wt) to determine the labeling index of normal colonic mucosa. In experiment 2, rats were given 20 weekly injections of DMH (20 micrograms/kg body wt) and received either saline or bombesin (10 or 30 micrograms/kg body wt) every other day for 24 weeks. Administration of bombesin significantly increased the labeling indices of colonic mucosa in a dose-dependent manner. Chronic administration of bombesin at both dosages with DMH caused significant increases in the incidence, number and depth of involvement of colon cancers; however, it did not affect the size and histological type of colon cancers. In addition, bombesin at the dose of 30 micrograms/kg significantly increased the labeling index of colon cancer. These results suggest that bombesin stimulates the cell proliferation of colonic mucosa and colon cancer and enhances colon carcinogenesis in rats.
Second Department of Surgery, Tokyo Medical and Dental University, Japan.
A
A
Ide
K
K
Yoshinaga
T
T
Iwama
Y
Y
Mishima
D019813:1,2-Dimethylhydrazine; D000818:Animals; D001839:Bombesin / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects; D003043:Cocarcinogenesis; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D004127:Dimethylhydrazines / Q000633:toxicity*; D004357:Drug Synergism; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D013268:Stimulation, Chemical
D002273:Carcinogens; D004127:Dimethylhydrazines; D019813:1,2-Dimethylhydrazine; D001839:Bombesin