PURPOSE:The somatostatin analog, octreotide, has previously been found to influence rectal sensation and may also influence anal resting pressure.METHODS:We studied the effect of octreotide on anal resting pressure and rectal compliance in eight healthy patients. Octreotide was administered intravenously as a bolus injection in doses of 100 and 10μgor as infusion of 250μg/hour on separate days and compared with placebo.RESULTS:Within one minute after a bolus injection of 100 μg of octreotide, anal resting pressure increased from 56±12 to 96±16 cm H2O(P<0.005). Octreotide had no effect on rectal sensitivity or compliance measurements. Octreotide counteracted rectoanal reflex by increasing anal pressure almost to the level found with an empty rectum.CONCLUSION:Somatostatin thus seems to contribute to the regulation of rectoanal reflex.