Effect of supplemental L-arginine in a chemical-induced model of colorectal cancer.
L-Arginine inhibits the development of spontaneous, transplantable solid tumors and chemically induced mammary tumors. The aim of the present study was to investigate the effect of l-arginine on chemically induced colorectal cancer in male Wistar rats. Colorectal cancer was induced in all animals by weekly subcutaneous injections of the colonic procarcinogen 1,2-dimethylhydrazine (DMH) at a dosage of 20 mg/kg body weight. Arginine was given in a 1% solution of drinking water. Group I was the DMH control; group II, arginine for 22 weeks; group III, arginine for the first 10 weeks only. Lymphocyte function was evaluated by measuring the thymic lymphocyte proliferative response to the T cell mitogen phytohemagglutinin. The results show that tumor incidence and tumor burden (tumors/rat and tumors/tumor-bearing rat) were significantly reduced in both groups of animals receiving arginine compared to DMH controls (p < 0.05). The tumor areas and volumes were also reduced in both arginine groups (p < 0.05). Thymic lymphocyte stimulation indices were significantly increased by arginine supplementation (p < 0.05). These results would be in keeping with the reduction in colorectal tumor production due to a "nonspecific" stimulation of the host immune system by L-arginine.
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Department of Surgery, Institute of Clinical Science, The Queen's University of Belfast, Grosvenor Road, Belfast BT12 6BJ, Northern Ireland, U.K.
Hoper
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M
Anderson
N
N
Rowlands
B J
BJ
D019813:1,2-Dimethylhydrazine; D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D002273:Carcinogens; D002455:Cell Division / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000139:chemically induced / Q000276:immunology / Q000517:prevention & control*; D004127:Dimethylhydrazines / Q000633:toxicity; D004195:Disease Models, Animal; D008213:Lymphocyte Activation; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology
D002273:Carcinogens; D004127:Dimethylhydrazines; D001120:Arginine; D019813:1,2-Dimethylhydrazine