Apelin (AP) and leptin (LEP) are adipokines with vasomotor actions. Taking into account the published data on the role of obesity in the development of pulmonary hypertension, we studied the implications of apelin on leptin relaxing effects on isolated rat pulmonary arteries. LEP had vasodilatatory effects on phenylephrine-precontracted rat pulmonary arteries from normal and ovalbumin-sensitized rats, but not on rats with monocrotaline-induced pulmonary hypertension. AP13 pretreatment increased LEP effects by one-half. Our studies revealed the existence of synergistic favorable effects of these adipokines on pulmonary vessels.