Rectal hyperpolarization following intestinal bypass for obesity.

The electrical potential difference across the rectal mucosa in six shunt-operated women was compared with that obtained in 26 normal females. The potential difference was considerably increased in all the patients, whereas the plasma concentrations and the transmural fluxes of sodium, chloride, and potassium were within normal ranges. Based on measurements of plasma renin and plasma aldosterone concentrations in three of the patients, the possibility of secondary hyperaldosteronism could be ruled out.