INTESTINAL TRANSPORT OF WATER, SODIUM AND GLUCOSE FROM AN ELECTROLYTESOLUTION WITH AND WITHOUT BICARBONATE

In this study we have evaluated the role of bicarbonate on water and s odium transport in normal and secreting ilea of rabbits as controversy exists regarding the inclusion of bicarbonate in oral rehydration sol ution (ORS). In anaesthetized rabbits 10 cm closed ileal loops were co nstructed and filled with 5 mi of an electrolyte solution with and wit hout bicarbonate, which contained polyethylene glycol (PEG; mol wt 4,0 00) as a nan-absorbable marker. The fluid was withdrawn after an hour and analyzed for PEG,sodium acid glucose. Similar studies were carried our in loops one hour after exposure to 1 mu g/ml of purified cholera toxin. Body temperature was maintained at 37 degrees C during the exp eriment by using a lamp. The mean +/-SE of water and sodium absorption , with bicarbonate versus without bicarbonate, was -1.4 +/- 0.1 vs -1. 1 +/- 0.3 ml/h/10cm, and -340.8 +/- 23.0 vs -308.4 +/- 35.6 mM/h/10cm, respectively from secreting rabbit ilea. A similar effect was observe d in normal ilea. It is concluded that bicarbonate containing electrol yte solution has no additional promoting effect on water and sodium ab sorption in normal or secreting ilea of rabbits.