Are non-absorbable indicators of comparable value in the human stomach made abnormal by taurocholic acid?
1. The substances chromium-51 (51CrCl3) and phenolsulphonphthalein (phenol red; PR) were compared as non-absorbable indicators in the human stomach after alteration of ionic permeability by taurocholic acid. 2. Control and test solutions containing 10 mM taurocholic acid and indicators at pH 1 were instilled into the stomach and sampled immediately and after 15 min. The ratios of the initial and final concentrations of the indicators (Ci/Cf) were compared. 3. Correlation coefficients of the Ci/Cf ratios for the two indicators were 0 with 91 in control studies and 0 with 75 after taurocholic acid instillation; there was no significant difference between either indicator. During taurocholic acid instillation, Ci/Cf values tended to fall compared to controls. 4. In a smaller number of subjects in whom polyethylene glycol (PEG) was also measured as a non-absorbable indicator, results were similar to those obtained with 51Cr and PR. 5. 51Cr, PR and PEG are comparable indicators in the norma
