DNA adduct formation by 2-amino-3-methylimidazo [4,5-f] quinoline (IQ) in rat colon. 2001

C X Lin, and Y Monden, and A Umemoto
Second Department of Surgery, University of Tokushima School of Medicine, Tokushima, Japan.

A food-born carcinogen, 2-amino-3-methylimidazo [4,5-f] quinoline (IQ) induces cancer in the rat colon. The mechanism for colonic DNA adduct formation leading to cancer by IQ was studied using a colostomized F344 rat model. In this model, the transverse colon of the rat was colostomized, which produced a fecal stream-positive proximal colon and a negative distal colon were produced. When IQ (50 mg/kg) was administered into the distal colon of the colostomized rats (n = 5), the ratio of the DNA adduct level of the distal colonic mucosa to the paired muscular layer 24 hr after dosage was 2.02, whereas that was 1.51 and 1.37 when IQ was administered into the stomach (n = 6) and the vein (n = 5), respectively. This suggested that luminal exposure of IQ induced DNA adduct formation. Since IQ (an amine form) has no reactivity toward DNA, these findings suggested that IQ was immediately activated in the absorbed mucosal cells and reacted with DNA. However, most of the IQ absorbed was metabolically activated in the liver, distributed by blood circulation, and formed DNA adducts in the colonic mucosa and muscular layer.

UI MeSH Term Description Entries
D007413 Intestinal Mucosa Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI. Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D008297 Male Males
D011804 Quinolines
D011916 Rats, Inbred F344 An inbred strain of rat that is used for general BIOMEDICAL RESEARCH purposes. Fischer Rats,Rats, Inbred CDF,Rats, Inbred Fischer 344,Rats, F344,Rats, Inbred Fisher 344,CDF Rat, Inbred,CDF Rats, Inbred,F344 Rat,F344 Rat, Inbred,F344 Rats,F344 Rats, Inbred,Inbred CDF Rat,Inbred CDF Rats,Inbred F344 Rat,Inbred F344 Rats,Rat, F344,Rat, Inbred CDF,Rat, Inbred F344,Rats, Fischer
D002273 Carcinogens Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included. Carcinogen,Oncogen,Oncogens,Tumor Initiator,Tumor Initiators,Tumor Promoter,Tumor Promoters,Initiator, Tumor,Initiators, Tumor,Promoter, Tumor,Promoters, Tumor
D003106 Colon The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON. Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D005753 Gastric Mucosa Lining of the STOMACH, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. The surface cells produce MUCUS that protects the stomach from attack by digestive acid and enzymes. When the epithelium invaginates into the LAMINA PROPRIA at various region of the stomach (CARDIA; GASTRIC FUNDUS; and PYLORUS), different tubular gastric glands are formed. These glands consist of cells that secrete mucus, enzymes, HYDROCHLORIC ACID, or hormones. Cardiac Glands,Gastric Glands,Pyloric Glands,Cardiac Gland,Gastric Gland,Gastric Mucosas,Gland, Cardiac,Gland, Gastric,Gland, Pyloric,Glands, Cardiac,Glands, Gastric,Glands, Pyloric,Mucosa, Gastric,Mucosas, Gastric,Pyloric Gland
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D015394 Molecular Structure The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds. Structure, Molecular,Molecular Structures,Structures, Molecular
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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