Induction curves showing the effects of different INDO treatment schedules on PCT formation in C.D2I/P mice. The groups labeled “start” were begun on the day indicated and maintained thereafter on INDO. The Off D70 group was treated for the first 70 days and then discontinued. All INDO-treated mice received the 20 μg/mL dose. There were originally 24 mice in the continuous treatment group, but the female mice died for unexplained reasons and this group contained only 12 mice. See Table 2 for numbers of mice and percentages of PCTs at 28-day intervals from day 125 to day 300.