ALT activity in the silkworm hemolymph injected with 0.4 M NAC prior to CCl
. Silkworms fasted for 6 h were injected with 0.4 M NAC or 0.9% NaCl (first injection), and then injected with 15% CCl4, 20% CCl4 or 0.9% NaCl (the second injection) 30 min later. The hemolymph was collected to measure ALT activity after 1 d incubation. The horizontal bar in each line indicates mean ALT activity in each group. *P < 0.01 and **P < 0.001 vs. 0.9% NaCl-0.9% NaCl, ***P < 0.01 vs. 0.9% NaCl-15% CCl4, and ****P < 0.001 vs. 0.9% NaCl-20% CCl4. (n = 5, 0.9% NaCl-0.9% NaCl; n = 7, other groups).