The effect of ionic and nonionic contrast media on the metabolism of prostaglandin E2 in rat lungs.

Pulmonary inactivation of prostaglandin E2 (PGE2) was investigated in isolated perfused rat lungs during infusion of ionic and nonionic radiographic contrast media (RCM). When 100 nmol of [14C]-PGE2 was infused slowly into the pulmonary circulation, the ionic ioglycamate decreased the metabolism of PGE2, but other ionic (diatrizoate and ioxaglate) and nonionic RCM (iopamidol and metrizamide) had no significant effect. When a smaller amount of [14C]-PGE2 (10 nmol) was injected as a bolus the metabolism of PGE2 was decreased also by diatrizoate and ioxaglate, but not by iopamidol. After a similar bolus injection of 10 nmol of [14C]-PGE2, the efflux of radioactivity from the lungs was increased by diatrizoate, ioglycamate and ioxaglate but remained unchanged by iopamidol and metrizamide. The RCM infusion did not change the perfusion pressure. The present study indicates that ionic RCM decrease the inactivation of PGE2 in rat lungs and thus possibly increase the circulating level of this prostaglandin.