Plasma beta-endorphin and adenosine concentration in pulmonary hypertension.
To determine whether beta-endorphin plays a role in the regulation of pulmonary vascular tone in patients with pulmonary hypertension, we investigated the relations between hemodynamics and beta-endorphin and adenosine concentrations in 3 clinical situations: (1) normal hemodynamics (7 subjects, mean pulmonary artery [PA] pressure 18.5 +/- 1 mm Hg); (2) moderate pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD) (8 patients, mean PA pressure 31 +/- 3 mm Hg); and (3) severe primary pulmonary hypertension (PPH) (8 patients, mean PA pressure 70 +/-5 mm Hg). Plasma beta-endorphin and adenosine were measured in a distal PA and in the femoral artery in room air and during oxygen inhalation. Beta-endorphin levels were similar in the pulmonary and systemic circulations. No difference was observed between patients with COPD and PPH, but relative to controls, both had significantly higher beta-endorphin levels. Pulmonary adenosine was significantly lower in patients with pulmonary hypertension than in controls (-60% in COPD [p <0.005] and -70% in PPH [p <0.001]). Pure oxygen administration significantly decreased adenosine and beta-endorphin levels, much more so in patients with COPD and PPH. We found a negative correlation between beta-endorphin and adenosine concentrations (r = -0.751, p <0.001): the higher the adenosine, the lower the beta-endorphin level. These observations suggest that because adenosine release by pulmonary vascular endothelium is reduced in pulmonary hypertension, the resulting worsened hypoperfusion and tissue oxygenation may cause increased beta-endorphin release.
Saadjian
A Y
AY
Cardiology Department, Institut National de la Santé et de la Recherche Médicale, Service de Cardiologie, CHU Nord, Marseille, France.
Paganelli
F
F
Juin
M A
MA
Devaux
C
C
Lévy
S
S
Guieu
R P
RP
D000241:Adenosine / Q000097:blood*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood* / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D008173:Lung Diseases, Obstructive / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy; D011379:Prognosis; D011669:Pulmonary Wedge Pressure; D011863:Radioimmunoassay; D001615:beta-Endorphin / Q000097:blood*
D015415:Biomarkers; D001615:beta-Endorphin; D000241:Adenosine