title: Thyroid tumours in rats and hepatomas in mice after griseofulvin treatment.
abstract: Griseofulvin, an antibiotic used to treat dermatophystosis, was tested for carcinogenicity in mice, rats and hamsters. Three groups of mice and rats were given the drug in powdered diet in alternating 5-week periods for life, at dose levels of 3.0%, 1.5% and 0.3% (mice) and 2.0%, 1.0% and 0.2% (rats). A group of mice and 3 groups of hamsters received continuous daily treatment for life with griseofulvin at 3.0%, 1.5%, 0.3% and 0.1% dose levels respectively. A significant incidence of hepatic tumours was observed at the 2 higher treatment levels in mice. Also, statistically significant rates (P less than or equal to 0.001 and/or P less than or equal to 0.020) of thyroid tumours, indicating a dose-response, were recorded in male rats at the 2.0%, 1.0%, and 0.2% dose levels, and in females at the 2.0% and 1.0% dose levels. Hamsters did not develop neoplasms in response to treatment at any level.
mesh_terms: D000236:Adenoma / Q000139:chemically induced* / Q000473:pathology; D000284:Administration, Oral; D000818:Animals; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D005260:Female; D006118:Griseofulvin / Q000633:toxicity*; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008297:Male; D008647:Mesocricetus; D051379:Mice; D009374:Neoplasms, Experimental / Q000139:chemically induced; D051381:Rats; D013964:Thyroid Neoplasms / Q000139:chemically induced* / Q000473:pathology
chemical_list: D006118:Griseofulvin