To evaluate indicators of inflammatory changes in the airways of young smokers we have measured the levels of several eicosanoids in bronchoalveolar lavage (BAL) fluid of 18 female smokers (age 33 +/- 2 years) and 9 female non-smokers (age 29 +/- 2 years) who were hospitalized for treatment not related to any pulmonary disease. In each BAL specimen the following eicosanoids were determined by radioimmunoassay: prostaglandin (PG) E2; PGF2 alpha; 9 alpha, 11 beta-PGF2, a metabolite of PGD2; 6-keto PGF1 alpha, a metabolite of prostacyclin; thromboxane (Tx) B2, a metabolite of TxA2; the 5-lipoxygenase products 5-hydroxy-eicosa-tetraenoic acid (HETE), leukotriene (LT) B4 and LTC4; the 12-lipoxygenase product 12-HETE; and the 15-lipoxygenase product 15-HETE. The concentrations of the cyclooxygenase products (pg ml-1) in the BAL fluid of the non-smokers were: PGE2 15.4 +/- 1.9, PGF2 alpha 7.6 +/- 1.0, 9 alpha, 11 beta-PGF2 8.7 +/- 1.8, TxB2 8.8 +/- 1.3, and 6-keto PGF1 alpha only 1.5 +/- 0.8. The concentration of the lipoxygenase products were: 15-HETE 781 +/- 200, 12-HETE 193 +/- 33, 5-HETE 14.0 +/- 3.1, LTC4 9.5 +/- 3.1, LTB4 6.2 +/- 1.4. BAL fluid from smokers contained two- to three-fold higher levels of TxB2 and PGF2 alpha (P less than 0.05). The levels of TxB2 and PGF2 alpha were positively correlated to the number of package years (rs = 0.55 and rs = 0.65, P less than 0.02). The concentrations of 5-, 12- and 15-HETE tended to be higher in BAL fluid from smokers, but this was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)