The actions of 5-, 12-, and 15-HETE on tracheobronchial smooth muscle.

In view of the likelihood that monohydroxyeicosatetraenoic acids (HETEs) are produced in asthma we investigated the actions of these lipoxygenase products on a range of tracheobronchial smooth muscle preparations. 5- and 15-HETE contracted human isolated bronchial muscle and guinea-pig lung strip but were less potent and less effective than histamine. In contrast 5-, 12- and 15-HETE were inactive on guinea-pig and cat tracheae. In addition to its direct action, subthreshold doses of 5-HETE (0.001-0.01 micrograms ml-1) potentiated histamine-induced contractions of human isolated bronchial muscle. The latter effect may suggest that 5-HETE plays a significant role in the airway hyperreactivity commonly associated with asthma.