Figure 7.

Diagram depicting the prostanoid synthesis pathway and the effects of PGE₂ on its receptor subtypes. Highlighted boxes identify prostaglandin-related genes that are upregulated in the gastric antrums of Lep^ob tissues. We hypothesize that upregulation of PTGES, encoding microsomal PGE₂ synthase, results in increased levels of PGE₂, which in turn results in abnormal antral slow wave and contractile activity. The PTGER1–3 receptors are also upregulated and likely play a role in the altered gastric motor activity. IP₃, inositol triphosphate.