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Progression of alachlor‐induced olfactory mucosal tumours
Author(s) -
Genter Mary Beth,
Burman Dawn M.,
Bolon Brad
Publication year - 2002
Publication title -
international journal of experimental pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.671
H-Index - 72
eISSN - 1365-2613
pISSN - 0959-9673
DOI - 10.1046/j.1365-2613.2002.00243.x
Subject(s) - alachlor , olfactory mucosa , nasal cavity , medicine , intestinal metaplasia , pathology , carcinogen , respiratory mucosa , metaplasia , cancer , respiratory system , physiology , gastroenterology , biology , olfactory system , anatomy , atrazine , pesticide , genetics , psychiatry , agronomy
Summary. Alachlor is an herbicide used primarily in the production of corn (maize), peanuts, and soybeans and is associated with cancer of the nasal cavity, thyroid, and stomach in rats. Previous work from our laboratory demonstrated that the nasal cavity tumours originate from the olfactory mucosa, and that neoplasms were present following 6 months of exposure (126 mg/kg/day in the diet). The studies presented herein were conducted to determine more precisely the earliest time point at which alachlor‐induced tumours were present, and to describe the histological changes that occur en route to tumour formation. We determined that dramatic histological changes, including respiratory metaplasia of the olfactory mucosa, were present following 3 months of exposure, and the earliest alachlor‐induced olfactory mucosal tumours were detected following 5 months of treatment. Because alachlor is positive in short‐term mutagenicity assays with olfactory mucosal activation, and because of the relatively short time‐to‐tumour formation observed with alachlor, we also conducted a ‘stop’ study in which rats were treated with alachlor for 1 month and then held without further treatment for an additional 5 months. This study demonstrated that abbreviated alachlor exposure did not result in subsequent tumour formation within the 6‐month observation period.