Effect of reducing sodium or glucose concentration in a hypo-osmolar ORS (oral rehydration salts) on absorption efficiency: marker perfusion study in rat jejunum.

We evaluated the relative absorption efficiency of reducing the sodium or glucose concentration to make an ORS hypo-osmolar in a perfusion model. In nine adult albino rats 30 cm of jejunum was perfused at 0.4 ml/min with three glucose salt solutions for 45 min each, one with 60 mM sodium, 111 mM glucose, and osmolarity 247, one with 90 mM sodium, 60 mM glucose, and osmolarity 250, and one with 90 mM sodium, (111 mM) glucose, and osmolarity 301 (control solution). Each contained 2 g/L polyethylene glycol 4000 as a marker. The net water and sodium absorption were 2.8 (P < 0.001) and 2.6 (P < 0.001) times higher from low-sodium and 1.7 (P < 0.001)- and 1.5 (P < 0.001)-fold higher from low-glucose solutions compared to the control. Net glucose absorption was 2.2 (P < 0.001)-fold higher from low-sodium solutions compared to the control. The net water, sodium, potassium, and glucose absorptions were 1.6 (P < 0.001)-, 1.7 (P < 0.001)-, 1.36 (P < 0.05)-, and 4.15 (P < 0.001)-fold higher from low-sodium compared to low-glucose solutions. The hypo-osmolar ORS with reduced sodium was substantially more absorption efficient compared to the one with reduced glucose.