title: Long-term ingestion of reduced glutathione suppressed an accelerating effect of beef tallow diet on colon carcinogenesis in rats.
abstract: OBJECTIVE
  We have shown previously that long-term feeding of beef tallow increases colorectal cancer in rats. This study investigated the effects of enzymic antioxidant, reduced glutathione (GSH), on colon carcinogenesis in rats fed with beef tallow.
  
  
  METHODS
  Colon carcinogenesis was induced by intraperitoneal injection of azoxymethane (AOM) to rats. Rats were fed with 10% beef tallow supplemented with or without 1% GSH in drinking water. Aberrant crypt foci (ACF) and expression of beta-catenin in colonic mucosa were examined at 12 weeks. Cancers, related substances of oxidative stress and arachidonic acid cascade in plasma and normal colonic mucosa were determined at 44 weeks.
  
  
  RESULTS
  GSH attenuated the number of ACF increased by beef tallow, but GSH had no influence on expression of beta-catenin increased by AOM. Incidence of colon cancer was no different with or without GSH, but GSH attenuated the number of colon cancers in each rat. GSH suppressed plasma malondialdehyde concentration. GSH increased GSH concentration and activities of catalase, glutathione peroxidase and superoxide dismutase in colonic mucosa, and decreased cyclooxygenase-2, prostaglandin E2 and thromboxane B2 levels.
  
  
  CONCLUSIONS
  This study indicated that GSH suppressed the number of ACF, but the attenuation of colon carcinogenesis was limited to the number of colon cancers, although anti-oxidative effects and suppressive effects of arachidonic acid cascade were demonstrated by several indexes. These results suggested that colon carcinogenesis enhanced by beef tallow was partly caused by oxidative stress and arachidonic acid cascade, which were reduced by GSH.
authors: Department of Internal Medicine and Gastrointestinal Endoscopy, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan. ryosuke-shiraishi@nifty.com
authors: Ryosuke
authors: R
authors: Shiraishi
authors: Takehiro
authors: T
authors: Fujise
authors: Tsukasa
authors: T
authors: Kuroki
authors: Takashi
authors: T
authors: Kakimoto
authors: Lujie
authors: L
authors: Miao
authors: Yasuhisa
authors: Y
authors: Sakata
authors: Seiji
authors: S
authors: Tsunada
authors: Takahiro
authors: T
authors: Noda
authors: Ryuichi
authors: R
authors: Iwakiri
authors: Kazuma
authors: K
authors: Fujimoto
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D016718:Arachidonic Acid / Q000378:metabolism; D001397:Azoxymethane / Q000633:toxicity; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000201:enzymology / Q000453:epidemiology / Q000517:prevention & control*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004195:Disease Models, Animal; D005223:Fats / Q000633:toxicity; D005978:Glutathione / Q000494:pharmacology*; D005980:Glutathione Reductase / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects; D011230:Precancerous Conditions / Q000473:pathology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D051176:beta Catenin / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005223:Fats; D051176:beta Catenin; D016718:Arachidonic Acid; C013698:tallow; D051546:Cyclooxygenase 2; D005980:Glutathione Reductase; D005978:Glutathione; D001397:Azoxymethane