Pulmonary NAD+-linked 15-hydroxyprostaglandin dehydrogenase activity is decreased by cigarette smoking.

Male rats were exposed to freshly generated cigarette smoke once daily for 4 to 13 weeks. Inhalation of smoke was verified by elevated level of carboxyhemoglobin. NAD+-dependent 15-hydroxyprostaglandin dehydrogenase activity, the key enzyme responsible for biological inactivation of prostaglandins, was found to decrease in lung but not in kidney or stomach following cigarette smoke exposure. The consequence of impaired pulmonary metabolism of prostaglandins and thromboxane may result in alteration of vascular homeostasis and subsequently lead to cardiovascular disorders commonly found in smokers.