To the Editor: It is still unclear whether somatostatin acts locally or systemically. Somatostatin-containing cells are frequently juxtaposed to their target cells, and they may exert their influence locally. On the other hand, somatostatin secretion by the islets of Langerhans is well established in vitro, and usually the compounds that stimulate the in vitro release augment in vivo somatostatin levels in portal venous blood.1,2 However, with a few exceptions3,4 fluctuations in peripheral blood are very small. Degradation of somatostatin by isolated hepatocytes has been reported.5 In an investigation of the importance of the liver in clearance of somatostatin, fasting plasma. . . No extract is available for articles shorter than 400 words.