Vasoactive peptides in a pulmonary embolism model

Purpose. To investigate changes in atrial natriuretic peptide (ANP) and angiotensin 11 (AT-II) levels in a canine model of pulmonary embolism (PE), created by embolizing the left posterior pulmonary artery with gelatin powder. Methods. Pulmonary arterial pressure (PAP) was measured before, immediately after, and I day after pulmonary artery embolization. Plasma ANP and AT-II levels were measured by radioimmunoassay (RIA) before and 1, 3, 7 14, 2 1, and 28 days after embolization. ANP and AT-II levels were also measured by RIA in both embolized and nonembolized lung tissue 28 days after embolization. Results. No changes in plasma ANP or AT-II were seen within 28 days after embolization. Although the ANP level in the nonembolized lung tissue was significantly increased, the level in the embolized lung tissue was significantly decreased compared with that of sham-operated control lung tissue. The AT-II level in the nonembolized lung tissue was significantly decreased compared with that of the control lung tissue, but the level in the embolized lung tissue did not change. Conclusion. Both ANP and AT-II in the nonembolized lung tissue reacted to compensate for vasoconstriction caused by the PE in this model.