RESUMO
Two experimental models were tried in young molnourished rats in order to study effect of an hyperosmolar challenge in the small intestine on the bi-diretcional fluxes of sodium. Wealning rats were with emergy restricted diets. In model I 1mL of NaCl900 mOsm/kg was introduced in the smal intestine of the rats left from 5 up to 70 min, in order to determine the moment of higher net Na secretion, which occurred at 10 min. In model II, the bi-directional fluxes of Na and Cl- were studied using Na Cl or mannitol 900 mOsm/kg under the effect of mecholil, atropine or 2-4 dinitrophenol, for 10 min. Mecholil decreased the Na absorption enhancing the net secretion. Control rats were used as reference. In the restricted diets animals occurred an increase of the net secretion stimulated by NaCl 900 mOsm/kg, and this effect was enhanced by mecholil. It is suggested that in malnutrition there is an impairment in Na- intestinal absorption.