The metabolism of prostaglandin E2 is decreased by high- and medium-tar but not by low-tar cigarette smoke in isolated rat lungs.

The effects of smoke from low-, medium- and high-tar cigarette brands on the metabolism of prostaglandin E2(PGE2) were investigated in isolated rat lungs. When isolated lungs were ventilated with smoke of high- or medium-tar cigarettes during an infusion of PGE2 into the pulmonary circulation, the amount of unmetabolized PGE2 was increased and that of 15-ketometabolites (15-keto-PGE2 and 13,14-dihydro-15-keto-PGE2 together) was decreased in the perfusion effluent compared to air ventilated control lungs. This decrease in the pulmonary metabolism of PGE2 was seen by both filter and non-filter high/medium-tar cigarettes. When isolated rat lungs were ventilated with smoke of low-tar cigarettes no change in the metabolism of PGE2 was detected. The pressor response of the vascular bed to the infusion of PGE2 was inhibited with smoke of both low- and high-tar cigarettes.