Endothelin-1: increased plasma clearance, pulmonary affinity and renal vasoconstriction in young smokers

Pulmonary and renal haemodynamics and elimination of endothelin-1 (ET-1) we re studied in six young smokers in response to 20 min intravenous infusion of ET-1 (4 pmol kg(-1) min(-1)) after smoking. At 20 min of ET-1 infusion f ractional ET-1 extractions in the lungs and kidneys were 60 +/- 2 and 60 +/ - 7%, respectively. Cardiac output and renal blood flow (RBF) fell by 18 +/ - 4% (P<0.05) and 34 +/- 5% (P<0.01). Mean systemic arterial pressure incre ased (P<0.05) whereas pulmonary pressures were unchanged. Compared with pre viously published data in non-smokers (Weitzberg et al., 1991, 1993) basal arterial ET-1 and ET-1-values during ET-1 infusion were lower with a more r apid return to basal value. Smokers had higher pulmonary extraction of ET-1 at the same pulmonary arterial concentration (P<0.05). RBF reduction was m ore pronounced (P<0.05). Systemic vascular resistance increased while pulmo nary vascular resistance did not increase as in non-smokers. Increased plas ma clearance and more efficient pulmonary elimination of ET-1 lowers the ar terial level in young smokers. In addition ET-1 evokes more pronounced rena l vasoconstriction in these individuals.