title: Induction of glutathione S-transferase placental form positive foci in liver and epithelial hyperplasia in urinary bladder, but no tumor development in male Fischer 344 rats treated with monomethylarsonic acid for 104 weeks.
abstract: The carcinogenicity of monomethylarsonic acid (MMA(V)), a major metabolite of inorganic arsenics in human and experimental animals, was investigated in male Fischer 344 rats. A total of 129 rats at 10 weeks of age were randomly divided into three groups and received drinking water containing MMA(V) at doses of 0 (Control), 50, and 200 ppm ad libitum for 104 weeks. No significant differences were found between the control and the MMA(V)-treated groups regarding clinical signs, mortality, hematological, and serum biochemistry findings. Quantitative analysis of glutathione S-transferase placental form (GST-P) positive foci in liver revealed a significant increase of numbers and areas in the 200 ppm MMA(V)-treated group. In the urinary bladder MMA(V) induced simple hyperplasia and significantly elevated the proliferating cell nuclear antigen (PCNA)-positive index in the urothelium. A variety of tumors developed in rats of all groups, including the controls, but all were histologically similar to those known to occur spontaneously in F344 rats and there were no significant differences among the groups. Thus, it could be concluded that, under the present experimental conditions, MMA(V) induced lesions in the liver and urinary bladder, but did not cause tumor development in male F344 rats even after 2 years exposure.
authors.affiliation: Department of Pathology, Osaka City University Medical School, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.forename: Hideki
authors.initials: H
authors.lastname: Wanibuchi
authors.forename: Elsayed I
authors.initials: EI
authors.lastname: Salim
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Doi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Yoshida
authors.forename: Ginji
authors.initials: G
authors.lastname: Endo
authors.forename: Keiichirou
authors.initials: K
authors.lastname: Morimura
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukushima
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology*; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000096:biosynthesis*; D006965:Hyperplasia; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis*; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D008297:Male; D011230:Precancerous Conditions / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D051381:Rats; D011916:Rats, Inbred F344; D001743:Urinary Bladder / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D019459:Urothelium / Q000187:drug effects / Q000201:enzymology / Q000473:pathology
chemical_list: D001152:Arsenicals; D007527:Isoenzymes; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; C496558:Gstp1 protein, rat; C020300:monomethylarsonic acid