Aldosterone modulates glucose absorption in the jejunum post colectomy

Abstract

The main function of the colon is water and electrolyte absorption. Total colectomy eliminates this colonic function and may alter the absorptive capacity of the small intestine for nutrients. We have previously examined the effect of total colectomy on glucose absorption in the jejunum in rats and found that glucose absorption increases 2 weeks post colectomy. To investigate whether a hormonal mechanism regulating sodium absorption mediates this change in glucose absorption, we have treated colectomized rats with injections of an aldosterone inhibitor spironolactone. Total colectomy with ileo-rectal anastomosis was performed on anesthetized adult male Sprague Dawley rats (N=6). Sham rats (N=6) were identically handled without colon resection. The two groups were allowed to recover for 2 weeks. A third group of colectomized rats (N=6) received at 2 days post colectomy a daily spironolactone injection (10 mg/Kg/ml sesame oil) for 2 weeks. Glucose absorption was measured by the in vivo single-pass perfusion technique. Jejunal segments were perfused with a solution containing radiolabelled glucose and phenol red. Glucose (20 mM) absorption was determined 2 weeks post colectomy. Glucose absorption significantly decreased to 5 ±1.5 μmol/hr.cm in colectomized spironolactone-injected rats compared to 13.4 ±2.5 μmol/hr.cm in colectomized untreated rats and 9.2 ±1.6 μmol/hr.cm in normal rats (p<0.05). No significant variation in glucose absorption was observed in sham rats compared to normal rats. Our results suggest that aldosterone modulates glucose absorption in the small intestine post-colectomy, possibly through a sodium-dependent mechanism.