Arachidonate-enriched triglyceride oil does not promote tumor development in a rat medium-term multi-organ carcinogenesis model

• Published in: Food and chemical toxicology 2012-08, Vol.50 (8), p.2780-2791
• Main Authors: Imai, Norio, Kawabe, Mayumi, Tamano, Seiko, Doi, Yuko, Nakashima, Hironao, Suguro, Mayuko, Numano, Takamasa, Hara, Tomomi, Hagiwara, Akihiro, Furukawa, Fumio, Kaneda, Yoshihisa, Tateishi, Norifumi, Fujii, Wataru, Kawashima, Hiroshi, Shibata, Hiroshi, Sakakibara, Yutaka
• Format: Article
• Language: English
• Subjects: Animals; Arachidonate-enriched triglyceride oil; arachidonic acid; Arachidonic Acid - administration & dosage; bioassays; Biological and medical sciences; bladder; Body Weight; carcinogenesis; Carcinogenesis, carcinogens and anticarcinogens; carcinogens; cell proliferation; Cell Transformation, Neoplastic; Chemical agents; Drinking Behavior; F344 rats; Feeding Behavior; Female; females; glutathione transferase; kidneys; large intestine; liver; Male; mammary glands; Medical sciences; Multi-organ carcinogenesis bioassay; Neoplasms, Experimental - pathology; No tumor promotion; oils; Organ Size; Rats; Rats, Inbred F344; tissues; Toxicology; triacylglycerols; Triglycerides - administration & dosage; Tumors; uterus
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2012.05.004

► This study investigated the tumor modifying potential of arachidonate-enriched triglyceride (ARA-oil) in F344 rats. ► A rat medium-term multi-organ carcinogenesis bioassay was used. ► ARA-oil did not exert promoting potential on tumor development in any organs/tissues examined. ► No-effect level on tumor promotion of ARA-oil was 5% in diet in both sexes. The modifying potential on tumor development of arachidonate-enriched triglyceride oil (ARA-oil) containing approximately 40% arachidonic acid was investigated in a medium-term multi-organ carcinogenesis bioassay using male and female F344 rats. The animals were sequentially given five carcinogens with different target sites in the first 4weeks, and then administered ARA-oil for 24weeks at dietary levels of 0% (control), 1.25%, 2.5% or 5.0%. No statistically significant differences in incidences and multiplicities of hyperplastic and neoplastic lesions were showed in the large intestine in either sex. In the liver, kidney, and lung in both sexes, and the mammary gland and uterus in females, tumor promoting potential was not evident with ARA-oil treatment. ARA-oil did not affect the quantitative data for glutathione S-transferase placental form positive foci of the liver. Increased induction of hyperplastic or neoplastic lesions in the urinary bladder and thyroid in ARA-oil-treated groups was without dose dependence. In addition, a second experiment with ARA-oil only administration for 8-week revealed no effects on cellular proliferation in the urinary bladder or thyroid in either sex. These results indicate that ARA-oil has no tumor promoting potential in any organs or tissues initiated with the five carcinogens applied in the present study.