title: Pentachlorophenol inhibits micronuclei induction by 2-acetylaminofluorene but not by thioacetamide.
abstract: Our study examined the capacity of pentachlorophenol (PCP) to inhibit the ability of 2-acetylaminofluorene (2-AAF) and thioacetamide (TAA) to induce micronuclei in mouse bone marrow cells in vivo. 2-AAF (5.6mg/kg) and TAA (60mg/kg) were administered intra-peritoneally (i.p.) to Mus musculus males (BALB/c), and the frequencies of polychromatic erythrocytes with micronuclei (PCE-MN) 24h after injection were analyzed. Treatment with 2-AAF or TAA resulted in high PCE-MN frequencies in comparison with untreated and negative controls (19.9 and 21.6‰, respectively, versus ≈3‰). Pretreatment with a single PCP dose (44mg/kg) 24h prior to the 2-AAF administration virtually eliminated micronuclei formation by 2-AAF, although it had no inhibitory effect on TAA-induced micronuclei. Animals receiving cyclophosphamide (CP) served as positive control. Since PCP is known to inhibit arylsulfotransferase (AST) activity, which is involved in 2-AAF activation, this mechanism most likely produced the results with PCP and 2-AAF. Our results also are consistent with a different pathway involved in TAA induction of micronuclei, one that is not inhibited by PCP.
authors.affiliation: Laboratorio de Genética Toxicológica (GENETOX), Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad del Bío-Bío, Casilla 447, Chillán, Chile.
authors.forename: E
authors.initials: E
authors.lastname: Zamorano-Ponce
authors.forename: J Fernández
authors.initials: JF
authors.lastname: Romero
authors.forename: P
authors.initials: P
authors.lastname: Rivera Caamaño
authors.forename: C Barrios
authors.initials: CB
authors.lastname: Guerra