INCREASED PLASMA-CONCENTRATIONS OF ENDOTHELIN-1 DURING AND AFTER PULMONARY SURGERY

We studied the involvement of endothelin-1 (ET-1) in the physiological response to surgical stress. Plasma concentrations of ET-1 were measured by a sandwich-type enzyme immunoassay. The blood samples were collected from the pulmonary artery (PA), the left atrium (LA), and the median cubital vein (MCV) in four patients who had undergone pulmonary lobectomy. The samples were collected before, during, and after surgery. Plasma ET-1 concentrations increased in the blood from all sampling sites. The highest concentration of plasma ET-1 was observed at 6 h after surgery in MCV (3.97 +/- 1.47 pg/ml, mean +/- SD) and at the end of surgery in PA (1.79 +/- 0.48 pg/ml) and in LA (1.93 +/- 0.43 pg/ml). These values returned to the baseline value within 72 h after surgery [1.21 +/- 0.19 (MCV), 1.00 +/- 0.18 (PA)]. Although the lung has a large capacity to remove ET-1 from the circulating blood, ET-1 concentrations measured in plasma samples obtained from the LA were not different from those obtained from the PA. This may suggest that the lungs have the ability to absorb and release ET-1 simultaneously during pulmonary surgery. The increase of ET-1 in MCV was greater than that in PA or in LA. This suggests the possibility of ET-1 release from the forearm.