Digestive Diseases and Sciences, Vol. 32, No. 10 (October 1987), pp. 1092-1096 Effect of Somatostatin Analog on Water and Electrolyte Transport and Transit Time in Human Small Bowel MARIA I. DUENO, MD, JULIO C. BAI, MD, WILLIAM C. SANTANGELO, MD, and GUENTER J. KREJS, MD The present study was undertaken to investigate how a somatostatin analog (201-995 Sandoz), which is now commonly used for treatment of patients with gut hormone- producing tumors, affects water and ion absorption and transit time in the normal jejunum. Six healthy volunteers were given somatostatin analog intravenously at a dose of 1 txg/kg/hr. At the same time, jejunal water and ion movement and transit time were measured using the triple-lumen tube technique [perfusion of a plasma-like electrolyte solution with PEG as a nonabsorbable marker at a rate of 15 ml/min; dye dilution curves ([3H]mannitol, [14C]PEG, BSP) for determination of jejunal transit time]. During soma- tostatin analog administration, transit time through a 30-cm segment of perfusedjejunum increased from 4.0 min to 17.0 min. While the somatostatin analog increased jejunal transit time, it had no effect on net water and electrolyte absorption under steady-state conditions. The effect of somatostatin analog on the proximal small bowel is similar to the action of an eight-times higher dose of intravenous native somatostatin previously studied. The effect of the analog on transit time suggests a potentially beneficial effect in patients with large-volume diarrhea in which no tumor or circulating secretagogue can be identified, such as in pseudopancreatic cholera syndrome. KEY WORDS: somatostatin analog; small bowel transit time; intestinal absorption; antidiarrheal action. In patients with secretory diarrhea due to circulat- ing agents, administration of intravenous somato- statin can cause marked clinical improvement. Di- arrhea has been abolished or dramatically de- Manuscript received July 10, 1986; revised manuscript re- ceived December 16, 1986; accepted March 17, 1987. From the Department of Internal Medicine, The University of Texas Health Science Center at Dallas, Southwestern Medical School, Dallas, Texas. This study was supported by USPHS grant M01-RR-00633 and by grants from the Ruby D. Hexter Estate, Dallas, Texas; and Sandoz Pharmaceuticals, East Hanover, New Jersey. Address for reprint requests: Dr. Guenter J. Krejs, Depart- ment of Internal Medicine, Karl-Franzens-University, Auenbrug- gerplatz 15, A-8036 Graz, Austria. creased in patients with VIPomas and malignant carcinoid syndrome (1-5). At least four mechanisms are conceivable to explain how somatostatin could elicit this effect: (1) enhancement of normal water and ion absorption in the intestine, (2) inhibition of secretion at the mucosal level, (3) decreased release of a secretagogue from tumor, and (4) delay of intestinal transit and thus prolonged contact time between luminal contents and mucosal surface. With regard to these possibilities, several obser- vations have been made previously: (I) In healthy subjects somatostatin infusion does not enhance net jejunal water and electrolyte transport when exam- ined by perfusion techniques (6). (2) While somato- 1092 Digestive Diseases and Sciences, Vol. 32, No. 10 (October 1987) 0163-2116/87/1000-1092505.00/0 9 1987 PlenumPublishing Corporation