THE STOMACH IS A SOURCE OF LEPTIN

The circulating peptide leptin, which is the product of the ob gene(1) , provides feedback information on the size of fat stores to central O b receptors(2,3) that control food intake and body-weight homeostasis( 4-6). Leptin has so far been reported to be secreted only by adipocyte s(1) and the placenta(7). Here we show that leptin messenger RNA and l eptin protein are present in rat gastric epithelium, and that cells in the glands of the gastric fundic mucosa are immunoreactive for leptin , The physiological function of this previously unsuspected source of leptin is unknown. However, both feeding and administration of CCK-8 ( the biologically active carboxy-terminal end of cholecystokinin) resul t in a rapid and large decrease in both leptin cell immunoreactivity a nd the leptin content of the fundic epithelium, with a concomitant inc rease in the concentration of leptin in the plasma. These results indi cate that gastric leptin may be involved in early CCK-mediated effects activated by food intake, possibly including satiety.