Somatostatin inhibits fluid secretion in the rat jejunum

We determined the effect of somatostatin on water, glucose, sodium, and urea transport by utilizing an in vivo perfusion technique in the rat jejunum. Somatostatin (2.5-37.5 micrograms/kg . min) infused intravenously had no effect on basal absorption of water, sodium, or urea. However, infusion of somatostatin at the rate of 10 micrograms/kg . min completely blocked prostaglandin E1-induced inhibition of water absorption (P less than 0.01) and partially blocked net water secretion induced by theophylline (P less than 0.001). This effect of somatostatin occurred despite unchanged basal or theophylline and prostaglandin E1-stimulated cyclic AMP levels. In contrast, somatostatin did not affect glucose absorption in the rat jejunum. These results demonstrate that somatostatin may affect water and electrolyte movement by blocking the action of cyclic AMP in the rat jejunum.