Immunohistochemical expression of somatostatin receptor subtypes in various normal human tissues

Somatostatin is a tetradecapeptide, which mediates its action via five receptor subtypes (sst1–5). Because of the inhibitory and antiproliferative effects, long-acting somatostatin analogues were developed. While octreotide binds with high affinity to sst2a only, the new analogue SOM230 demonstrates high affinity to sst1, 3 and 5 in addition.