Antagonism of vasopressin-induced water flow by somatostatin

The ability of somatostatin to modify the water premeability of the toad bladder was examined. Somatostatin had a small effect on basal water flow and antagonized the hydrosmotic effect of vasopressin. Water flow induced by cyclic AMP was enhanced. These results may explain the diuretic and hyposthenuric effects of somatostatin in vivo.