13C-methacetin breath test reproducibility study reveals persistent CYP1A2 stimulation on repeat examinations

Figure 1 Time course of the ¹³CO₂ content within the total pool of exhaled CO₂ after peroral administration of 75 mg ¹³C-methacetin in 20 healthy volunteers who each underwent three breath tests on separate days. Filled rectangles represent the time points at which the rise in ¹³CO₂ concentration was statistically significantly different from the baseline measurement, open rectangles stand for values not statistically different from the baseline. The values shown are mean ± SE.