Effect of hypoxia on release of vasoactive substances from cultured pulmonary arterial and aortic endothelial cells.

The effect of hypoxia on the production and release of vasoactive substances from endothelial cells of pulmonary artery (PAECs) and aorta (AECs) was studied. The results indicated that the overall effect of the long half-life vasoactive substances released from PAECs and AECs was vasoconstrictive. The long half-life lipid-soluble substances produced by PAECs and AECs were vasodilative, and did not change in hypoxia. However, the long half-life water-soluble heat-unstable and heat-stable ones were vasoconstrictive. Hypoxia could reduce the release of the former and promote that of the latter which might be peptides. The PAECs could release specific long half-life mediator which was pulmonary artery-constrictive, water-soluble, heat-unstable, and not related to hypoxia. Hypoxia inhibited the production of PGI2, a short half-life vasodilator, in PAECs, but not in AECs.