Cardiovascular effects of a PEGylated apelin

► N-terminal conjugated 40 kDa PEG apelin-36 was successfully produced. ► PEGylation had minimal effect on APJ receptor binding affinity. ► Comparable in vitro bioactivity was observed between PEG-apelin-36 and apelin-36. ► Inotropic effect and circulation time were prolonged with PEG-apelin-36. ► Apelin-36 and PEG-apelin-36 had no effect on blood pressure.