 This study is conducted to examine how GSK2586881, a recombinant human ACE2 peptide, modulates the acute hypoxic pulmonary vasoconstriction HPV response in healthy volunteers. The study will be single-center, randomized, placebo-controlled and double blind sponsor open. Subjects will be randomized to receive a single intravenous IV dose of GSK2586881 or placebo saline in a crossover design. The primary objective of the study is to evaluate the effect of a single IV dose of GSK2586881 on the HPV response in healthy volunteers during exercise under hypoxic conditions. Approximately 35 subjects will be enrolled for a maximum of 56 days. 