Abstract
The activation of macrophages by several agents results in the formation of arachidonic acid metabolites via the cyclooxygenase and lipoxygenase pathways. It has been shown that in human alveolar and peritoneal macrophages after stimulation by the calcium ionophore A23187, the main substances formed are LTB 4 and 5-HETE and also TxB 2. In rat this profile of eicosanoid formation was identical in alveolar macrophages, however a pronounced difference was observed in peritoneal macrophages, which predominantly generated the cyclooxygenase products 6kPGFI~ and TxB 2 [1]. Several of these eicosanoids have effects on the contractility and vascular permeability of lung tissue. Furthermore it has been reported that they are involved in the pathological effects of asthma and inflammatory diseases. In the experiments described here, the effects of the chemotactic peptide FMLP (formyl-methionylleucyl-phenylalanine) and PAF-acether (platelet activating factor) on the formation of eicosanoids from [1-14C]-arachidonic acid labelled resting and stimulated guinea-pig alveolar macrophages were determined. It was the aim of the study to investigate whether substances released from these macrophages could contribute to the bronchoconstriction induced by PAF-acether [2].
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