Table 1. Total ion current measurements of cholesterol (Ch) and deuterated cholesterol (D7Ch) in rat retina and brain tissue

These measurements are based on experiments like the one shown in Figure 3. In order to adequately quantify both ions, samples were run at three different concentrations. The cholesterol values were determined from the diluted injections to avoid detector "dead time". In case of the brain samples only the most concentrated (D7Ch) and most dilute (Ch) were useful for quantifications. In the pooled retina sample, the D7Ch value is an average of three measurements normalized for dilution. The Ch value is based on the average of the two measurements from the intermediate and highest dilutions.