Positive response of 2-acetylaminofluorene, negative response of 4-acetylaminofluorene in the mammalian spot test

Evaluation of 2AAF in a dose of 400 mg/kg led to positive results. The frequency of colour spots in all cases was higher in the experimental sets than in the control sets, but only in one experiment with pure DMSO as vehicle were they statistically significant. 4AAF tested under similar dosage and treatment conditions always yielded negative findings.