INCREASE IN ATRIAL-NATRIURETIC-FACTOR IN THE LUNGS, HEART, AND CIRCULATORY-SYSTEM OWING TO OZONE

Ozone can cause pulmonary edema and simultaneously decrease blood pres sure. Atrial natriuretic factor (ANF) may mediate both of these effect s in that it increases pulmonary capillary permeability resulting in e dema formation and vasodilates the vascular system. The present invest igation was designed to test directly the effect of ozone on the conte nt of ANF in the lungs, heart, and the circulatory system. Ozone (0.5 ppm) exposure for 8 h increased ANF content in the lungs fourfold (13. 33+/-2.7 ng/g tissue) in six Fischer 344 rats compared with ANF conten t (3.03+/-0.2 ng/g tissue) in six Fischer 344 rats exposed only to roo m air. Ozone increased ANF content in the heart fivefold in the same a nimals from 288+/-39.6 ng/g tissue in the rats exposed to room air to 1,473+/-234.8 ng/g tissue in those exposed to ozone. Ozone also double d the concentration of ANF in the circulatory system. This study demon strates that ozone does increase ANF in the lungs, heart, and circulat ory system, suggesting that ANF may mediate the decreased blood pressu re and pulmonary edema observed with ozone exposure.