ABSTRACT
UNLABELLED: The composition of the World Health Organisation (WHO) solution in oral rehydration therapy has remained controversial because of its total osmolarity (303 mosm/L) and higher sodium concentration (90 mEq/L), increasing the risk of hypernatraemia. AIM OF THE STUDY: To compare the efficacy of two reduced-osmolarity oral rehydration solutions (S1: 268 mosm/L and 50 mEq/L Na(+); S2: 240 mosm/L and 60 mEq/L Na(+) ) with the WHO recommended formula taken as the reference solution. Water, electrolytes and glucose fluxes were directly measured in vivo, in isolated ligated loops of rat jejunum (n=12). Intestinal secretion was induced by exposing jejunum to cholera toxin (CT=20 microg/loop). RESULTS: All three test solutions similarly reversed cholera toxin-induced net water absorption (3.37 +/- 1.35; 3.31 +/- 0.43 and 3.13 +/- 0.66 microL/min.cm(2) for S1, S2 and WHO solutions respectively). However, net Na secretion induced by cholera toxin was observed with S1 and S2 while Na absorption occurred with the WHO solution. CONCLUSION: For a same amount of water absorbed, Na absorption from reduced - osmolarity rehydration solutions is lower than with the WHO solution. Our data may contribute to a better rationale for the use of orally administered hydration solutions in man.
