Effect o f Wood Combustion Smoke Inhalation on Angiotensin-l-Converting Enzyme in the D og

One lung of each dog was exposed to smoke from burning pine wood, while the other was subjected to acute hypoxia. Angiotensin-l-converting enzyme (ACE) activity in biopsied tissue of the smoke-exposed lung was markedly increased immediately after the injury and even higher 30 min­ utes later. No change in ACE activity was observed in the hypoxic con­ tralateral lung. Serum ACE activity did not change significantly following anesthesia and before smoke inhalation. Serum aldosterone and cortisol levels increased at this juncture. Smoke inhalation caused intra-alveolar hemorrhages and edema. Pulmonary and systolic, diastolic and mean pres­ sures, pulmonary capillary, wedge pressure, cardiac output and systemic and pulmonary arteriolar resistances remained unchanged throughout the experiment. The changes of ACE activity are presumably a direct effect of smoke inhalation. They are seen as an early response of the lung endo­ thelial cells to many types of injury (chronic hypoxia, bleomycin or monocrotaline administration) and may represent an im portant step in the development of the organ’s response to the injury.