Stimulation of active and passive sodium absorption by sugars in the human jejunum.

Abstract

A B S T R A C T The effects of glucose and fructose on water and sodium absorption in the human jejunum were compared to assess the relative contribution of active and passive sugar stimulation of sodium transport. The effect of fructose is assumed to be entirely passive, and the difference between the effects of fructose and glucose is assumed to be a measure of sugarstimulated, active sodium absorption. Water and sodium movement with mannitol was the base line. Three sets of test solutions with differing sugar concentrations were studied. Fructose stimulated 66-100% as much net sodium and water absorption as glucose. Fructose stimulated potassium absorption, whereas glucose stimulated potassium secretion. Urea absorption was stimulated by both sugars. Glucose and fructose stimulated sodium absorption when chloride was the major anion, but they had relatively little effect on net sodium movement when chloride was replaced by bicarbonate or sulfate.It is concluded that glucose stimulates passive and active sodium transport in the human jejunum. Stimulated active sodium absorption generates an electrical potential across the mucosa that causes sodium (and potassium) secretion and partly or completely nullifies the effect of active sodium transport on net sodium movement. Net sodium absorption stimulated by glucose is mainly (66-100%) the passive consequence of solvent flow. The accompanying anion determines the degree to which sugars stimulate sodium absorption (Cl > SO4> HCO3). The effects of bicarbonate and sugars on jejunal sodium absorption are not additive.

Management of patients with a short bowel

“…In hot weather, due to water and sodium loss in sweat, patients with a stoma are more likely to have problems of dehydration. As the sodium content of jejunostomy (or ileostomy) effluent is relatively constant at about 90 mmol·L -1 and as there is coupled absorption of sodium and glucose in the jejunum [87][88][89] ; patients are advised to sip a glucose-saline solution with a sodium concentration of at least 90 mmol·L -1 throughout the day. The World Health Organization (WHO) cholera solution has a sodium concentration of 90 mmol·L -1 [90] and is commonly used (without the potassium chloride) ( Table 3).…”

“…The concentration of sodium in this solution is much higher than many commercial preparations used to treat infective or traveller's diarrhoeas. There is no evidence that the sodium bicarbonate adds to the effectiveness of this solution [89] and it may be more palatable if the sodium bicarbonate is replaced by sodium citrate. If the sodium concentration is increased further (e.g.…”

Oral rehydration solution normalizes plasma renin and aldosterone levels in patients with ulcerative colitis after proctocolectomy

“…ENaC mediates Na+ entry through the apical membrane, whereas SGLT-1 facilitates co-transport across the luminal membrane. Glucose in the enterocyte is transported into the blood by glucose transporter type 2 (GLUT2) through the basolateral membrane [17][18][19][20] . These mechanisms are believed to contribute to the improvement of post-colectomy diarrhea.…”

Comparison of oral sucrose and glucose electrolyte solutions in the out-patient management of acute gastroenteritis in infancy

“…It is also clear that when glucose solutions are made up incorrectly there is a greater risk of producing hyperosmolar feeds. In addition fructose liberated by sucrose hydrolysis also has a similar action (Fordtran, 1975) to glucose in promoting absorption of sodium and water. Nalin (1975) has shown oral glucose to be more effective than sucrose in adults with cholera, but a study in Indonesia by Moenginah et at.…”