Erythropoietin does not have effects on the ventilatory and pulmonary vascular response to acute hypoxia in men and women

Sustained and chronic hypoxia lead to an increase in pulmonary ventilation (hypoxic ventilatory response, HVR) and to an increase in pulmonary vascular resistance (hypoxic pulmonary vasoconstriction, HPV). In this study, we examined the effect of a clinical c.v. dose of recombinant human erythropoietin (50 IU kg(-1)) on the isocapnic HVR and HPV in seven male and seven female subjects by exposing them to hypoxia for 20 min (end -tidal P-o2 similar to 50 mmHg) while measuring their ventilation and estimating pulmonary arterial pressure from the maximal velocity of the regurgitant jet over the tricuspid valve during systole (Delta P-max) with echocardiography. In the placebo session, after 5 and 20 min men responded with an increase in ventilation by 0.0056 and 0.0023 1 min(-1) kg(-1) %S-p02(-1), respectively, indicating the presence of hypoxic ventilatory depression. In women, the increase in ventilation was 0.0067 and 0.0047 1 min(-1) kg(-1) -%S-pO2(-1), respectively. In both sexes, erythropoietin did not alter these responses significantly. In the placebo session, mean Delta P-max increased by 6.1 +/- 0.7 mmHg in men (P = 0.035) and by 8.4 +/- 1.4 mmHg in women (P = 0.020) during the hypoxic exposure, whereby women had a similar to 5 mmHg lower end -tidal P-CO2. Erythropoietin did not alter these responses; in men, Delta P-max increased by 7.5 +/- 1.1 mmHg (n.s. versus placebo) and in women by 9.7 +/- 2.2 mmHg (n.s. versus placebo). We conclude that women tended to have a greater HPV in placebo conditions and that a clinical dose of erythropoietin has no effect on the HVR and HPV in either sex.