An endogenous agonist of the APJ receptor; induces calcium mobilization in APJ-Gαq16 cells expressing human APJ (EC50 = 0.18 nM); inhibits HIV-1 and HIV-2 infection in NP-2/CD4/APJ cells (mean IC50 = 63 UG/ml); inhibits or stimulates the expression of genes associated with apoptosis, mitosis, and DNA repair in IEC-6 and Caco-2 cells, respectively, at 0.01 µM; induces the production of NO in HUVECs from 100-1,000 nM; increases gastric acid secretion, as well as stomach histamine synthesis and secretion in rats from 20-100 UG/kg; reduces MAP in rats at 15 UG/kg