Similarities and differences in the transcriptional regulation of the leptin gene promoter in gastric and adipose cells

The stomach was reported to synthesize and secrete leptin mainly in the gastric lumen. Gastric leptin release is markedly increased after food intake, by vagal cholinergic stimulation and by cholecystokinin and secretin. Here we show that human gastric MKN-74 cells produce leptin that increases upon challenge with cholecystokinin, insulin, glucocorticoids and all-trans retinoic acid through activation of the leptin gene promoter. In addition, we demonstrate that forskolin and BRL37344 which increased cAMP levels, fail to affect the activity of leptin gene promoter in MKN74 expressing β3-adrenoceptor cells but, induce a 2-fold decrease in this activity in adipose 3T3-L1 cells. These data described for the first time, similarities and more interestingly, differences in the regulation of the leptin gene promoter in gastric cells as compared to adipocytes.