Absorption and clearance of ingested propofol. Mean ± SEM propofol concentration (nanogram propofol per milligram tissue) is plotted on a logarithmic scale relative to time (in hours) during propofol exposure (1.0 mM, horizontal bar, from zeitgeber time 0 to 6) and afterward for up to 48 h (N = 3 replicates derived from five flies each). A model fit (curve) for each set of data points (heads and whole flies) was produced by a weighted least squares regression fit to a three compartment first-order pharmacokinetic model.