title: Chronic dietary toxicity/oncogenicity studies on 2,4-dichlorophenoxyacetic acid in rodents.
abstract: Forms of 2,4-dichlorophenoxyacetic acid (collectively known as 2,4-D) are herbicides used to control a wide variety of broadleaf and woody plants. Doses in the 2-year chronic/oncogenicity rat study were 0, 5, 75, and 150 mg/kg/day. The chronic toxicity paralleled subchronic findings, and a NOEL of 5 mg/kg/day was established. A slight increase in astrocytomas observed (in males only) at 45 mg/kg/day in a previously conducted chronic rat study was not confirmed in the present study at the high dose of 150 mg/kg/ day. Doses in the 2-year mouse oncogenicity studies were 0, 5, 150, and 300 mg/kg/day for females and 0, 5, 62.5, and 125 mg/ kg/day for males. No oncogenic effect was noted in the study. In summary, the findings of these studies indicate low chronic toxicity of 2,4-D and the lack of oncogenic response to 2,4-D following chronic dietary exposure of 2,4-D in the rat and mouse.
authors.affiliation: Charles, Conn, & van Gemert, LLC, Durham, North Carolina 27705, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Charles
authors.forename: D M
authors.initials: DM
authors.lastname: Bond
authors.forename: T K
authors.initials: TK
authors.lastname: Jeffries
authors.forename: B L
authors.initials: BL
authors.lastname: Yano
authors.forename: W T
authors.initials: WT
authors.lastname: Stott
authors.forename: K A
authors.initials: KA
authors.lastname: Johnson
authors.forename: H C
authors.initials: HC
authors.lastname: Cunny
authors.forename: R D
authors.initials: RD
authors.lastname: Wilson
authors.forename: J S
authors.initials: JS
authors.lastname: Bus
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000633:toxicity*; D000818:Animals; D015197:Carcinogenicity Tests; D004032:Diet; D005260:Female; D006540:Herbicides / Q000633:toxicity*; D008297:Male; D051379:Mice; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D013045:Species Specificity
chemical_list: D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid