Somatostatin Stimulates Sodium and Chloride Absorption in the Rabbit Ileum

Abstract

The effect of somatostatin on ion transport in the rabbit ileum was determined. Somatostatin (a) decreased that short circuit current (Isc) (-1.0 +/- 0.2 mueq/hr . cm2) and potential difference (PD), (b) increased net Na and Cl absorption (+1.5 +/- 0.3 and +2.4 +/- 0.4 mueq/hr . cm2, respectively), and (c) increased tissue conductance (+5.1 +/- 1.3 mmhos/cm2). The increase in net Na and Cl absorption was primarily due to an increase in mucosal-to-serosal movement of these ions. Somatostatin had no effect on 3-0-methyl-glucose absorption, nor the increase in Isc produced by either 3-0-methyl-glucose or glucose. Phentolamine did not reverse the decrease in Isc produced by somatostatin and catecholamine depletion with reserpine or 6-OH-dopamine did not inhibit the somatostatin-induced decrease in Isc. The cholinergic agonists, carbachol and bethanechol, and no effect on somatostatin-induced decrease in Isc and atropine neither affected Isc nor blocked the effect of somatastatin on Isc. These studies demonstrate that somatostatin increased both Na Na and Cl absorption across rabbit ileal mucosa and suggest that these effects do not involve adrenergic or cholinergic agonists. Somatostatin may have a direct effect on the enterocyte.