1. Three weeks after partial enterectomy in the rabbit there was an increased somatostatin concentration and a decreased number of somatostatin-binding sites (without changes in the corresponding affinity values) in the cytosol of the residual intestinal tissue, except in the terminal ileum and the colon.
2. Five weeks after surgery both the somatostatin concentration and the number of somatostatin-binding sites returned towards control values.
3. These results suggest that an increase in bowel somatostatin content could lead to down-regulation of somatostatin-binding sites in the intestinal mucosa.