Perfused and ventilated guinea-pig lung: a method for evaluating xenobiotic effects on arachidonic acid using formaldehyde.

Lipoxygenase as well as cyclooxygenase pathways of arachidonic acid (AA) metabolism are involved in antigen-induced bronchoconstriction in ovalbumin-sensitized guinea-pig lungs. Chemical lung challenge induced by aerosol containing formaldehyde (5 ppm up to 20 ppm) was effective in increasing thromboxane (TX) B2 release in a dose-dependent manner, without affecting leukotriene (LT) release. This suggests that xenobiotics acting by non-immunologic mechanisms on bronchial mucosa may stimulate the cyclooxygenase pathway of AA metabolism, which, in turn, might cause bronchial and/or lung parenchymal effects of pathophysiological relevance.