Mutant frequencies (± standard error) in liver and testes from fish
analyzed 5, 15, 20, or 30 days after 1-h exposure to 0 or 120
mg/liter ENU. Mutant frequencies in liver increased
insignificantly over mean background (4.4 ± 0.7 ×
10−5) at 5 days (5.1 ± 0.8 ×
10−5), 4-fold at 15 days (15.6 ± 1.8 ×
10−5), 6-fold at 20 days (25.1 ± 2.3 ×
10−5), and 7-fold at 30 days (29.8 ± 2.0 ×
10−5). Mutant frequencies in testes increased 5-fold over
mean background (2.0 ± 0.6 × 10−5) at 5 days
(10.3 ± 1.1 × 10−5), 10-fold at 15 days
(19.6 ± 1.2 × 10−5), and 9-fold at 20 and 30
days (17.5 ± 1.6 × 10−5). –○–,
ENU-exposed liver; –●–, ENU-exposed testes; -
-○- - control liver; - -●- -, control testes.