Effects of somatostatin on food intake in rats

We examined the possibility that somatostatin, a tetradecapeptide distributed in the gut and the central nervous system, may influence food intake and behavior in rats. Although intravenously infused somatostatin did not alter food intake in 8 hour fasted rats, intracerebroventricularly infused somatostatin resulted in a biphasic response, first increasing then decreasing food intake. We also observed that the effects of somatostatin vary depending upon whether animals are fed or fasted. In fed rats, food intake was decreased, while in fasted rats food intake was increased. These results suggest that somatostatin can act in the central nervous system to stimulate appetite; but that other factors, possibly related to gut motility or clearance, may inhibit further feeding once the stomach is full.