Apelin-12 is a highly potent C-terminal fragment of a polypeptide that exhibits a strong affinity towards the orphan receptor APJ. It plays a role in maintaining body fluid balance and regulating feeding control in the central nervous system. Additionally, Apelin-12 functions as an inhibitor of HIV-1 entry through the APJ receptor and demonstrates neuroprotective properties.

Apelin-12 (A12) exerts neuroprotective effect against ischemia-reperfusion injury by inhibiting JNK and p38 MAPK signaling pathway in mouse[1]. Administration of exogenous A12 reduces arterial blood pressure in anesthetized rats due to activation of endothelial nitric oxide synthase and exerts a positive inotropic action in failing myocardium of rodents[2]. Apelin-12 stimulates acid secretion through an increase of histamine release in rat stomachs[4].